Last updated: November 2026
Pain in one knee usually has an obvious cause. But when many joints ache at once, or your muscles and joints hurt all over, it can be confusing. Here are the 10 most common causes, what makes each one different, and when to see a doctor.
1. A viral infection
Flu, COVID-19 and many other viruses cause body-wide aches in muscles and joints along with fatigue and fever. This usually clears up as you recover, although some viruses can cause joint pain that lingers for weeks.
2. Osteoarthritis
The most common type of arthritis, caused by wear of the cartilage that cushions joints. It usually affects knees, hips, hands and the spine, and pain tends to be worse after activity and at the end of the day.
3. Rheumatoid arthritis and other autoimmune conditions
Rheumatoid arthritis typically affects the same joints on both sides of the body, often hands and wrists, with morning stiffness lasting more than 30 minutes, swelling and warmth. Lupus and psoriatic arthritis can also cause widespread joint pain.
4. Fibromyalgia
Widespread pain in muscles and soft tissues, plus fatigue, poor sleep and brain fog. Joints may feel painful even though they aren’t damaged.
5 to 10: Other common causes
- Overuse or a new workout: muscle and joint soreness after unaccustomed exercise.
- Low vitamin D: linked with muscle and bone aches.
- Underactive thyroid: can cause muscle aches, stiffness and fatigue.
- Gout: sudden, very painful attacks, often in the big toe.
- Lyme disease and other tick-borne infections.
- Medications: some, including statins, can cause muscle aches.
Relief that helps most people
- Keep moving. Gentle activity like walking, swimming and cycling keeps joints flexible.
- Strengthen the muscles around your joints to take load off them.
- Heat for stiffness, cold for swelling.
- Manage your weight: every extra pound adds load to knees and hips.
- Over-the-counter pain relievers can help short-term; ask your pharmacist which is safe for you.
- Sleep well: poor sleep makes pain feel worse.
When to see a doctor
See a doctor if joint pain lasts more than a few weeks, or comes with swelling, redness, warmth, morning stiffness, fever, a rash or unexplained weight loss. Blood tests and an exam can tell the difference between wear-and-tear, inflammation and other causes, and early treatment of inflammatory arthritis protects your joints.
FAQ
Why do my joints hurt all of a sudden?
A viral illness is a common cause of sudden, widespread aches. Sudden pain with swelling in one joint can be gout or an infection and needs prompt care.
Can stress cause joint pain?
Stress can increase muscle tension and make pain feel worse, and it’s linked with flare-ups of some conditions.
What is the best thing for aching joints?
Regular gentle exercise, strength training and weight management help most people over time.
Related reading
Sources: Arthritis Foundation; National Institute of Arthritis and Musculoskeletal and Skin Diseases.
Health note: This article is for general information and isn’t medical advice. Talk to your doctor about symptoms that are new, severe or getting worse.
