Chronic Pain: Causes, Types and Treatment

What chronic pain is

Short-term (acute) pain is a warning signal from an injury or illness and fades as tissue heals. Chronic pain persists for more than 3 months. The International Association for the Study of Pain splits it into:

• Chronic secondary pain: pain from an identifiable disease, such as arthritis, cancer, endometriosis or nerve damage.
• Chronic primary pain: pain that is itself the main condition, with significant distress or disability that another diagnosis does not fully explain. Fibromyalgia, chronic widespread pain, many cases of chronic low back pain, irritable bowel syndrome and chronic tension-type headache belong here. See chronic pain disorder.

How pain becomes chronic

With prolonged pain, nerves in the spinal cord and brain can become sensitized: they amplify signals and fire with less input. Light touch or normal movement can then hurt. This is real pain, not imagined. Stress, poor sleep, low mood and fear of movement increase this sensitivity, which is why treatment targets them as well as the body part that hurts.

Types of chronic pain

Many people have a mix. Someone with knee arthritis can also develop sensitization.

Common causes of chronic pain

• Back and neck pain: the most common causes. See chronic low back pain.
• Arthritis: osteoarthritis and inflammatory arthritis.
• Headache disorders: chronic migraine and tension-type headache.
• Nerve damage: diabetes, shingles, chemotherapy, trapped nerves, amputation (phantom limb pain).
• After injury or surgery: persistent post-surgical pain after operations such as hernia repair, mastectomy or knee replacement.
• Complex regional pain syndrome: severe, burning pain with swelling and color change in a limb after an injury.
• Pelvic and abdominal pain: endometriosis, chronic pelvic pain, IBS.
• Cancer and its treatment.

Risk factors

Older age, female sex, previous injuries, physically demanding or very sedentary work, obesity, smoking, poor sleep, depression and anxiety, past trauma, and low income all increase the chance of pain becoming chronic.

How chronic pain affects the rest of life

Chronic pain rarely travels alone. Common companions are:

• insomnia and unrefreshing sleep, which make pain feel worse the next day
• fatigue and difficulty concentrating ("brain fog")
• depression and anxiety, each present in a large share of people with chronic pain
• reduced activity, deconditioning and weight gain
• strain on work, finances and relationships

Treating these is part of treating the pain.

How doctors assess chronic pain

Your doctor will ask where the pain is, what it feels like, how it affects daily life, sleep and mood, what you have tried, and about red flags. They will examine the painful area and nerves. Tests are used to look for treatable causes, such as blood tests for inflammation or diabetes, X-rays or MRI. Normal scans do not mean the pain is not real. In nociplastic pain they are expected.

Pain scales (0 to 10) and function questionnaires help track progress. A good goal is often "being able to walk 30 minutes" or "sleeping through the night" rather than zero pain.

Treatment for chronic pain

Physical approaches (first line)

• Exercise: regular, gradually increased activity is one of the most effective treatments for most chronic pain. Walking, swimming, strength training, yoga and tai chi all help. Start low and build slowly; some extra soreness at first is expected.
• Physical therapy: tailored exercise, pacing and graded activity.
• Pacing: spreading activity through the day to avoid boom-and-bust cycles.

Psychological approaches

• Cognitive behavioral therapy (CBT) and acceptance and commitment therapy (ACT) reduce the impact of pain on life and mood.
• Pain reprocessing therapy and pain education help retrain the sensitized nervous system.
• Mindfulness and relaxation techniques reduce stress-related amplification.

Medicines

• Acetaminophen (paracetamol) and NSAIDs: useful for some arthritis and back pain. Follow the label dose; NSAIDs can harm the stomach, kidneys and heart with long-term use.
• Topical treatments: NSAID gels for knee and hand arthritis; lidocaine and capsaicin for localized nerve pain.
• Nerve pain medicines: certain antidepressants (such as duloxetine or amitriptyline) and anti-seizure medicines (gabapentin, pregabalin), prescribed by a doctor.
• Opioids: CDC guidance advises that they are not first-line for chronic pain, because benefits fade and risks of dependence and overdose rise with long-term use. When used, they should be at the lowest effective dose with regular review.

Procedures and other options

Joint injections, nerve blocks, radiofrequency ablation, spinal cord stimulation and surgery help selected people. Acupuncture and massage give modest benefit for some conditions. Multidisciplinary pain programs, combining several approaches, have the strongest evidence for complex chronic pain.

Living with chronic pain

• Keep a pain and activity diary to spot triggers and progress.
• Protect sleep with regular times and a wind-down routine.
• Stay connected with friends, work or volunteering where possible.
• Set small, specific goals.
• Plan for flare-ups: a short list of what helps (heat, a gentle walk, a relaxation recording) and when to seek help.

Frequently asked questions

What is the definition of chronic pain?

Chronic pain is pain that persists or recurs for longer than 3 months. It may be caused by an ongoing condition such as arthritis, or it may be a condition in itself, such as fibromyalgia, where the nervous system has become oversensitive to pain signals.

What causes chronic pain?

The most common causes are back and neck problems, arthritis, headache disorders, nerve damage, past injuries or surgery, and conditions like fibromyalgia and endometriosis. Long-lasting pain can also change how the nervous system processes signals, so pain continues even after tissues heal.

What is the best treatment for chronic pain?

There is no single best treatment. The strongest evidence supports combining regular graded exercise, physical therapy, psychological therapy such as CBT, and good sleep, with medicines chosen for the type of pain. Multidisciplinary pain programs work better than medicines alone for most people.

Can chronic pain go away?

Sometimes. Pain from a treatable cause, such as a joint replaced for arthritis, can resolve. Nociplastic pain can improve substantially with treatment that calms the nervous system. Many people do not reach zero pain but achieve much less pain and a full, active life.

Is chronic pain linked to depression?

Yes. Chronic pain and depression often occur together and worsen each other through poor sleep, inactivity and shared brain pathways. Treating depression often lessens pain, and some antidepressants treat both. If you have thoughts of self-harm, call or text 988 in the US.