What causes joint pain or arthritis?

Joint pain can result from injury, inflammation, infection, or age-related wear and tear. Arthritis, a major cause, occurs when the cartilage cushioning joints breaks down or when the immune system attacks joint tissues. Osteoarthritis is linked to aging and repetitive stress, while rheumatoid arthritis is autoimmune. Symptoms include stiffness, swelling, and reduced mobility. Other causes include gout, lupus, or infections. Maintaining a healthy weight, exercising, and avoiding joint overuse can help reduce pain. Severe cases may require medication or physical therapy to manage inflammation.