Joint pain can be caused by many reasons from moderate to serious. It can be a symptom of serious disease or disorder growing in the body and can happen due to relatively benign condition like joint or muscle sprain. It can be due to variety of reasons such as malignancy, trauma, infections, auto-immune disorders and other abnormal processes in the body.

Joint is a point where two bones meet. The ends of these bones are covered by the cartilages and the bones are held at a proper place by the ligaments and tendons. There is little space between the two bones in which synovial fluid is present which nourishes the cartilages and maintain their elasticity. Joint movement happens when muscles attached to these bones contract or expand. Cartilages and synovial fluid stop these bones from rubbing together and also work as shock absorbers. This is a delicate composition and any deviation due to injury, infection, swelling or other problems to any involved part can cause joint pain.

Some simple reasons for joint pain are over use of any particular joint, lifting heavy weight or sudden or jerky movement, any of which can sprain the muscles or ligaments to cause pain in the joint. Such pain can go away by applying mild pain relieving ointments or on its own

Mild infections like flu and viral infections may also promote joint pain however most of the time these infections are not serious apart from some types of viral infections which cause hepatitis B as these virus can infect synovial fluid between the bones of the joint to damage cartilages and promote swelling, redness and inflammation. Some bacterial and fungal infections can also cause pain in the joint.

Apart from moderate reasons like sprain and injury to muscles or ligaments there are few other causes of joint pain which are not so moderate. Ankylosing spondilitis is one the reasons which promote joint pain. This problem affects spinal area and area close to tail bone but can affect joints to cause pain and inflammation. Aching muscles caused due to muscle weakness or other disorders also causes pain in the joint as movement of joint is controlled by muscles.

Arthritic conditions also promote joint pain, osteoarthritis and variety of conditions of rheumatoid arthritis can cause severe pain in joints which may even restrict the movement of the joint and can be very debilitating. Some types of arthritic conditions caused by infections and auto-immune disorders can be life threatening. Arthritis caused due to any infection can infect the synovial fluid, can also cause cartilage damage and make ligaments lax. These conditions make the bones less protected during the movement to make joint immovable and cause unbearable pain.

Certain diseases can promote arthritic conditions which eventually cause joint pain. Fibromyalgia, Lyme disease, tendinitis, sickle cell disease are few such diseases. Gouty arthritis is one of the most frequently occurring diseases which also promote severe pain in the joint as crystals of uric acid flow in blood to damage the tissues of the joint.