Common causes of joint pain include conditions like osteoarthritis, rheumatoid arthritis, bursitis, tendinitis, and injuries. Osteoarthritis is the most common cause, affecting 40% of people with joint pain. It is a degenerative joint disease involving the breakdown of cartilage. Rheumatoid arthritis is an inflammatory condition affecting multiple joints and tissues. Diagnosis involves considering history, symptoms, examination and sometimes investigations. Treatment options depend on the underlying cause but may include medications, physiotherapy, exercise, weight loss, or in some cases surgery.