Pain

Overview

Pain is an uncomfortable physical and emotional experience that can range from mild to severe. Pain is a highly personal experience and a person’s own description of their pain is still the most important way to measure it. It can feel like pricking, tingling, stinging, burning, shooting, aching, throbbing, squeezing, or electric.

Pain is one of the body’s most important protective signals. It can help people avoid harm by warning the body about injury, infection, inflammation, a broken bone, or cancer. But persistent pain is not always a simple warning signal. When pain becomes chronic (lasting at least three months and often much longer), it may continue because the body and brain become more sensitive to pain signals, and how pain is processed and interpreted changes over time. Changes in brain activity with chronic pain include those that affect sensation, attention, emotion, memory, arousal, and behavior.

Pain is one of the most common reasons people seek medical care. While not all pain is curable, most pain can be treated. Pain management is often easier when care begins early and is matched properly to the cause of the pain, a person’s overall health, and their functional goals.

Signs and Symptoms

Pain can feel mild or severe. No two people feel pain the same way, even when the underlying cause is similar. Pain is a highly personal experience and a person’s own description of their pain is still the most important way to measure it.

Pain Described by How Long it Lasts

Acute pain starts suddenly and ends when its cause is treated or healed. The feeling of acute pain is usually sharp because it tends to act as a warning signal about a threat to the body from an injury, disease, overuse of a body part, or another environmental stress. Common causes include strained muscles, broken bones, tooth decay, surgery, childbirth, infections, and/or burns.

Episodic pain happens from time to time. It may be linked with a long-term medical condition, like sickle cell disease. Painful menstrual periods and chronic migraine are examples of episodic pain, which can occur on its own or after known triggers.

Chronic pain lasts for longer than three months or longer than the expected healing time. It can happen after an injury or illness, or it can happen without any physical injury. Chronic pain often has physical, mental, and social factors, along with changes in how the nervous system processes pain. When chronic pain restricts a person’s ability to do everyday activities like working, doing household chores, or caring for themselves, it is called high impact chronic pain.

Pain Described By its Cause

Pain can also be described by its most likely source. In many people, more than one pain source is present at the same time.

Nociceptive pain is caused by physical damage to the body and/or inflammation. It may feel sharp, dull, aching, throbbing, or tender, depending on the affected part of the body. Examples include pain from cuts, infections, broken bones, osteoarthritis, tendon injury, or after many surgeries.

Neuropathic pain is caused by damage to body nerves or to the brain and spinal cord. It is often described as burning, tingling, shooting, numb, lancinating, or electric. Examples include diabetic neuropathy, postherpetic neuralgia, radiculopathy, trigeminal neuralgia, traumatic nerve or spinal cord injury, and chemotherapy-related neuropathy.

Nociplastic pain arises from changes in how the body processes pain signals. It can’t be accounted for by an injury, inflammation, or disease of the body’s system for sensing touch and pain. People with nociplastic pain often also feel tired and don’t sleep well. They may also have problems with thinking and memory, altered moods, feel very sensitive to touch or other senses, and experience widespread tenderness. Examples include interstitial cystitis/bladder pain syndrome, some chronic low back pain, and some chronic headache disorders.

Common Types of Pain Described By its Location

Back pain is one of the most common medical problems in the United States. It can range from localized discomfort to widespread pain across the back. Depending on the cause and location, a person may experience:

• Increasing pain with lifting and bending
• Worsening pain when resting, sitting, or standing
• Pain that comes and goes
• Stiffness in the morning that lessens with activity
• Pain that radiates into the buttocks, leg, or hip
• Numbness or weakness in the legs or feet

Temporomandibular Disorders (TMDs) are one of the most common musculoskeletal conditions resulting in pain and disability. These disorders can lead to ongoing or repeated pain and difficulty moving the jaw, affecting the joint, nearby muscles, and supporting tissues. See the page on TMDs for more information.

Conditions Related to Increased Pain Sensitivity

Peripheral sensitization and central sensitization are changes in the body and brain that make a person more sensitive to pain and other sensations.

Hyperalgesia occurs when something already painful begins to feel even more painful.

Allodynia occurs when something previously not painful begins to feel painful, such as light touch on sunburned skin or in neuropathic pain.

Global sensory hyperresponsiveness occurs when a person becomes very sensitive to many or all sensations, including lights, noises, smells, movement, touch, and foods. This broader hypersensitivity is often experienced by people with nociplastic pain and migraine.

Related Health Effects

Living with any type of pain can be hard and can cause many other problems. Pain can:

• Get in the way of daily activities
• Disturb sleep and appetite or eating habits
• Make it difficult to continue working or attending school
• Reduce time with friends, family, and community

It is also common for pain, especially chronic pain, to affect a person’s emotions and mood. Many people with chronic pain describe anger, worry, sadness, guilt, grief, defeat, hopelessness, and frustration related to their pain. Depression, generalized anxiety disorder, and post-traumatic stress disorder (PTSD), are common in people with chronic pain. That is because pain processing overlaps with brain systems involved with emotion, threat, and arousal.

Research also shows that chronic pain can affect the body’s stress-hormone systems over time, which can influence pain sensitivity, sleep, tiredness, and the ability to cope.

Causes and Risk Factors

There is still a lot to learn about why people experience pain differently. Acute pain with an obvious cause, such as an infection or broken bone, is better understood than chronic pain. Research shows that biological, psychological, and social factors all shape pain. For this reason, pain is known as a biopsychosocial experience.

Biological Factors

Genetics

Many genes affect how a person senses pain, how likely chronic pain is to develop, and how well some treatments work. Some painful disorders also have genetic links. For example, ankylosing spondylitis and some migraine and neuropathy syndromes run in families.

In addition to the genes people inherit from their parents, stress, exercise, sleep, trauma, inflammation, and other life experiences can change how strongly pain-related genes are turned on or off over time without changing the DNA itself. This phenomenon is called epigenetics.

The Nervous System

Parts of the nervous system involved in the experience of pain overlap with systems involved processing and responding to emotion, threat detection, reward and motivation, attention and memory, body functions, and sensation. Changes in these systems can increase the risk of chronic pain and keep pain going even after the original injury improves.

The Immune System

Inflammation helps tissues heal after injury, but in some cases, the immune system becomes overprotective, and inflammation lasts longer than expected. In chronic pain, immune and other cells in the brain that support nerve function can interact with nerve cells in ways that increase pain signals and keep the body more sensitive to pain.

The Endocrine System

Stress-related hormones such as cortisol and adrenaline can send messages that make pain feel more or less intense. Hormones, sleep patterns, and the body’s stress response can affect pain and its symptoms, which is why better sleep and stress management can improve pain outcomes. Exercise can lead to changes that improve the body’s response to stress, while severe stress can lead to changes that make pain worse.

Other Physical Factors

Other physical aspects of the body can increase the risk for certain types of pain. For example, back pain is more common among people who are not physically fit. In some cases, this is because weak back and abdominal muscles may not properly support the spine. Weight gain can also put additional stress on the back and joints, increasing the risk for back pain and osteoarthritis. Age can also play a role, with back pain and pain from osteoarthritis becoming more common as someone ages.

Psychological Factors

Fear and avoidance

Although fear and avoidance (staying away from activities or movements out of fear they will cause pain or make it worse) can help protect a person from danger, they can also slow recovery from acute pain and contribute to the transition to chronic pain. Avoidance can increase disability and often stops people from doing activities they value, which can worsen physical health, mental health, and confidence inLearn more about talking with your doctor about complementary health approaches. recovery.

Emotions, mood, and mental health

Pain can affect a person’s emotions and mood, and negative emotions can also intensify a person’s experience of pain. Depression, generalized anxiety disorder, post-traumatic stress disorder (PTSD), and sleep problems are common in people with chronic pain. This is partly because the brain areas and pathways involved in processing and reacting to emotion and pain overlap. Learn about how to talk with a doctor or healthcare practitioner about mental health.

Beliefs and thoughts about pain

Research shows that beliefs and thoughts about pain affect a person’s experience of pain. Common ways of thinking in people with chronic pain include:

• Ongoing concerns about whether pain will go away or get worse can lead to hopelessness, anxiety, or depression when they continue for a long time.
• “Should” statements, meaning feeling pressure to live life the same way as before pain, can lead to frustration and disappointment.
• Blaming oneself, thinking the worst will happen (catastrophizing), and feeling helpless can worsen distress and disability, even when these reactions are understandable responses to pain.

Social Factors

Social factors, including income, education, access to healthcare, the safety of someone’s living conditions, work, trauma, and supportive relationships, can affect health outcomes and the experience of pain. Long-term stress from hardship and inequality can contribute to pain becoming chronic and differences in diagnosis, access to care, and outcomes.

Diagnosis

Pain is a subjective experience, meaning only the person experiencing pain can describe how much pain they feel and how it affects their life. There is no single blood test, scan, or device that accurately and completely measures pain in another person.

Describing pain clearly can help healthcare providers look for causes and choose treatments. Helpful information includes:

• How long you have had the pain
• Where you feel the pain and whether it stays in one spot, spreads out, or radiates
• How the pain feels and how severe it is
• Whether the pain is constant or comes and goes
• What activities, body positions, medicines, or treatments make it worse or better
• How often the pain occurs and how long it lasts
• Anything that seems to trigger the pain

Keeping a pain diary is a good way to track pain triggers and symptoms over time. A doctor may also ask a person to rate their pain on a scale of 0 to 10, or they may use pictures of faces showing different pain expressions.

After learning about a person’s pain history and other medical concerns, a doctor or other healthcare provider may perform physical exams, detailed assessments, and specific tests. Mechanism-based assessment (evaluating pain by identifying the underlying cause or process driving it) is an important approach, especially when a doctor or other healthcare provider suspects neuropathic or nociplastic pain.

Diagnostic tools may include:

• Physical and neurological examinations. These might examine movement, reflexes, sensation, balance, and/or coordination. They can also detect inflammation, joint swelling, poor circulation, focal weakness, or nerve involvement.
• Laboratory tests. Blood tests, and sometimes spinal fluid samples, can help diagnose infection, cancer, nutritional or hormonal problems, autoimmune disease, metabolic conditions, and other disorders.
• Imaging. Imaging tests like magnetic resonance imaging (MRI), computed tomography (CT), X-rays, or ultrasound can look inside the body’s structures and tissues. Other tests may include endoscopy, colonoscopy, or laparoscopy for digestive or pelvic pain when needed based on the patient’s condition.
• Electrodiagnostic procedures. Nerve conduction studies and electromyography (a test that measures the electrical activity of muscles) can help identify some nerve-related pain conditions. Some people may also need specialized testing, such as skin biopsy or quantitative sensory testing (tests of how the body senses touch and temperature) if a doctor or other healthcare provider suspects small nerve damage or sensory problems.
• Psychological assessments. These can identify factors such as fear, trauma, sleep problems, depression, anxiety, and coping needs in order to guide care to reduce disability and discomfort.
• Quality of life and functional assessments. These help healthcare providers better understand how pain is affecting a person’s life and daily activities.

Considerations For People That May Have Trouble Communicating Pain

Some people have trouble describing their pain, making diagnosis and treatment difficult. This includes people with Alzheimer’s disease, people with profound intellectual disabilities, and non-verbal individuals. Many behavioral challenges in these populations stem from undiagnosed and untreated pain. Signs of possible pain that caregivers should watch for and share with healthcare provides include facial expressions of pain, frequent position changes, trouble sleeping, sudden changes in behavior like increased agitation or moaning, and refusing to eat.

Treatment and Management

The goal of pain management is to improve quality of life and function so that a person can work, go to school, sleep well, and participate in daily activities. Treatment options vary depending on the type of pain, its duration, its likely cause, and a person’s age, other health conditions, and access to care.

While not all pain is curable, most pain can be managed. Most treatment plans focus on both reducing pain and improving function. No current treatment works for every type of pain or for every person, so care needs to be personalized.

Doctors recommend a whole-person, multi-treatment approach to prevent, assess, and treat chronic pain. For many conditions, non-medicine therapies and non-opioid medicines are often used first or along with opioids. Pain management teams may include primary care providers, pain management specialists, nurses, mental health clinicians, physical or occupational therapists, complementary and integrative healthcare providers, pharmacists, and social workers.

Medicines

Medicines used for pain should match the type of pain, a person’s age, other medical conditions, and the risks of side effects or drug interactions. Examples include:

• Acetaminophen may help some types of mild to moderate pain, but people with liver disease or heavy alcohol use should use this medicine only with careful guidance.
• Nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen and naproxen, can help inflammatory pain and many muscle and joint pain conditions. Long-term or improper use increases risk for stomach, kidney, and heart problems, especially in older adults and people with kidney disease, ulcers, or heart disease.
• Opioids may be used for certain cases of moderate to severe pain, especially in end-of-life situations or those involving acute, post-surgical, or cancer pain. However, opioids can cause sleepiness, constipation, slowed breathing, dependence, and overdose. For many chronic non-cancer pain conditions, non-opioid therapies are preferred, and opioid benefits are often modest relative to their risk.
• Antidepressants and antiseizure medicines can help some people, especially those with neuropathic pain or nociplastic pain who also experience poor sleep or mood symptoms. Examples include serotonin and norepinephrine reuptake inhibitors (SNRIs), certain tricyclic antidepressants, gabapentin, and pregabalin.
• Muscle relaxants can sometimes help short-term muscle and joint pain or muscle spasms, but they are not a universal long-term solution and may cause drowsiness or falls, especially in older adults.
• Topical medicines like diclofenac, lidocaine, or high-dose capsaicin can help some localized joint or neuropathic pain conditions.
• Newer non-opioid drugs are also emerging. Suzetrigine, a new medicine that targets pain signals in nerves, was approved by the FDA in 2025 for moderate to severe short-term pain in adults.

As people age, they are at higher risk for developing side effects from medicines. It is important to take exactly the amount of pain medicine a doctor or healthcare provider prescribes and to make sure the care team knows about all prescription medicines, over-the-counter medicines and dietary supplements, and amount of alcohol use.

Medical Procedures and Devices

Electrical stimulation of nerves or soft tissue can help some people with hard-to-treat pain. Options include:

• TENS (transcutaneous electrical nerve stimulation), which delivers mild electrical pulses through the skin to nerves and may provide short-term relief for some people
• Peripheral nerve stimulation, in which electrodes placed under the skin near nerves throughout the body send low-intensity electrical pulses to nerves
• Spinal cord stimulation, in which small wires are placed near the spinal cord and connected to a device under the skin that sends electrical signals to help reduce pain

Doctors may also suggest injections to block pain in a specific body area. These include steroid injections to reduce inflammation, botulinum toxin (Botox®) for chronic migraine, or trigger point injections for pain caused by muscle knots.

Other procedures may include:

• Nerve blocks use a numbing medicine to temporarily block pain signaling between specific areas of the body and the brain. An epidural injection is one common nerve block used during childbirth.
• Radiofrequency ablation uses heat to damage a small part of nerve tissue to reduce pain in certain conditions.
• Surgery may be helpful when pain is caused by something that can be corrected surgically, such as certain types of back pain, endometriosis lesions, nerve compression, a tumor, or joint arthritis.

Behavioral Medicine and Physical Therapy

Several behavioral and physical therapies can help some people with pain, especially when combined with education and a plan focused on daily function.

• Biofeedback helps people learn to control body functions involved in stress reactions, such as heart rate, breathing rate, and muscle tension.
• Cognitive behavioral therapy is a form of psychotherapy that helps people build skills to cope with emotions that come with pain. It includes balancing activity and rest to avoid flare-ups, relaxation, addressing thoughts that worsen pain, and mindfulness techniques.
• Counseling can help support people living with pain.
• Physical therapy can help a person recover after injury or surgery and manage their chronic pain through low-impact aerobic activity, stretching, strength training, walking, and gradually increasing movement.

Lifestyle Changes

Making lifestyle changes can also help reduce pain in some people:

• A diet that includes food that may help reduce inflammation in the body may help with some conditions that involve inflammation, although diet is only one part of overall care.
• Exercise and physical activity can help people with pain conditions build flexibility, muscle strength, and cardiovascular fitness. Research shows that regular exercise can help prevent low back pain and reduce how much back pain interferes with daily activities.
• Maintaining a healthy weight may help with pain in the knees, back, hips, or feet.
• Getting enough sleep can make pain feel less intense, support healing, and improve mood.
• Avoiding tobacco, a lot of caffeine, and alcohol can help because these substances can interfere with treatment, worsen sleep, and make pain problems worse in some people.

Complementary and Integrative Health Approaches

Research shows that some complementary and integrative (non-medicine) approaches can help people with certain pain conditions, especially when combined with education, activity, and psychological support.

• Acupuncture is a treatment in which a healthcare provider inserts very thin needles into the skin at specific body locations to help relieve pain.
• Chiropractic care or selected manual therapies use hands-on adjustments to the spine and joints to improve movement and reduce pain.
• Massage therapy uses pressure and movement of muscles and soft tissues to help relax the body and reduce pain.
• Tai chi, yoga, and other mind-body movement practices that combine movement, breathing, and focus may help reduce pain.

Learn more about talking with your doctor about complementary health approaches.

Cancer Pain

Cancer pain is a special concern. Many people fear cancer pain, but most pain from cancer or cancer treatment can be improved. Cancer pain often comes from several sources at once, such as tissue damage, inflammation, organ-related pain, and nerve injury. This is why this type of pain usually needs a combination of treatments. Breakthrough pain, which comes on quickly and can be very distressing, is one more reason to discuss a pain management plan as early as possible.

Living With Pain

It is important for a person to seek care if pain affects their life. Education, support, and treatment of other health conditions like problems with sleep, mood, and stress can improve chronic pain symptoms and overall function. It can be helpful for some people to:

• Get support for managing emotions, mood, and mental health conditions that are common in people with pain to reduce discomfort, muscle tension, and disability.
• Get support to identify helpful pain beliefs, pacing strategies, and recovery goals. These steps can improve a person’s ability to cope and reduce feelings of helplessness that are common in people living with chronic pain.

Pain Support Groups

Talking to other people living with pain can help people learn how to deal with their pain or the problems it creates. Support groups can also reduce isolation and help people feel believed and understood.

Unhealthy Coping Strategies

Some people who experience pain may overeat, smoke, and drink alcohol to cope with pain. However, these behaviors can make pain problems worse and lead to other health problems.

For example, mixing alcohol and acetaminophen can damage the liver. Mixing alcohol and aspirin increases the risk for stomach bleeding. Alcohol also increases the effects of opioids, which could lead to misuse and overdose. Over time, alcohol misuse can increase pain rather than relieve it.

Coping With Pain at the End of Life

Not everyone nearing the end-of-life experiences pain. If they do, the focus is on comfort, function, and relief of suffering, without letting fear of dependence prevent appropriate treatment.

Find Clinical Trials

Clinical trials uncover better ways to prevent, diagnose, treat, and understand diseases and conditions. To ensure results apply to everyone, volunteers of all ages, sexes, and backgrounds, including both healthy individuals and those with specific medical conditions, are needed. Find clinical trials on pain.

Find Treatment

If a doctor or other healthcare provider cannot help, people with pain should ask to see a pain specialist. Different types of healthcare specialists treat pain, depending on the cause:

• Pain specialists may include anesthesiologists, physiatrists, neurologists, or other clinicians with focused training in evaluation, diagnosis, and treatment of all different types of pain.
• Orthopedists treat and perform surgery for bone and joint diseases.
• Neurologists treat disorders and diseases of the brain, spine, and nerves.
• Neurosurgeons perform surgery for disorders and diseases of the brain, spine, and nerves.
• Physiatrists treat disorders involving the spine, muscles, nerves, and rehabilitation, and physical function.
• Rheumatologists specialize in treating muscle and joint diseases and autoimmune disorders.
• Physical therapists specialize in movement, mobility, and strengthening muscles.
• Orofacial pain specialists specialize in treating pain in the head and neck area, such as temporomandibular disorders (TMDs).

Community Support

The following organizations provide information and support for people living with pain:

• U.S. Pain Foundation
• American Academy of Orthopaedic Surgeons
• American Academy of Physical Medicine and Rehabilitation
• American Association of Neurological Surgeons
• American Chronic Pain Association
• American College of Rheumatology
• American Headache Society
• Arthritis Foundation
• National Headache Foundation

Note: This resource list is for informational purposes only. It is not comprehensive, and an organization’s inclusion does not constitute an endorsement by NIH. 

Research Information

The National Institutes of Health (NIH) is the largest public funder of biomedical research in the world. NIH invests most of its budget in medical research seeking to enhance life and to reduce illness and disability. NIH-funded research has led to breakthroughs and new treatments helping people live longer, healthier lives, and building the research foundation that drives discovery.

Scientists supported by the NIH are at the forefront of pain research. More than 20 NIH Institutes and Centers support pain research and are members of the NIH Pain Consortium, which identifies, coordinates, and supports pain research initiatives and strategic planning at NIH.

NIH funds a broad range of pain research, including exploration of pain neural pathways, the mechanisms of pain perception, neuropathic pain, inflammatory pain, nociplastic pain, migraine biology, and the transition from acute to chronic pain. Research efforts are ongoing to find biomarkers that can help clinicians better understand why a person is experiencing pain and to match treatments more precisely to mechanisms.

The Helping to End Addiction Long-term® Initiative, or NIH HEAL Initiative®, is an NIH-wide effort to speed scientific solutions to improve prevention and treatment strategies for opioid use disorder and enhance pain management. HEAL supports work on the biological causes of chronic pain and on the discovery and development of nonaddictive pain treatments.

The Brain Research Through Advancing Innovative Neurotechnologies®, or BRAIN Initiative, is accelerating the development of tools that provide a very close look at the inner workings of the brain and nervous system. Pain researchers are using these tools to study brain and nerve pathways and explore ways to adjust their activity to reduce pain.

Find NIH-funded research projects using NIH RePORTER, a searchable database of current and past research projects supported by NIH and other federal agencies.