Symptoms and Complications
The primary symptom of most types of tendinitis is pain. Some positions or movements can cause a greater degree of pain than others. You may also feel the lack of smoothness in the movement of the affected muscle. Sometimes, the tendon sheath fills with liquid and becomes inflamed. In other cases, it's dry and causes obvious friction when you move. In severe cases, tendons can rupture, causing increased pain and swelling and possibly permanent change in function of the respective muscle and joint.
Serious complications of tendinitis and tenosynovitis include muscle wasting and disability. The shoulder is the most vulnerable joint since it can freeze up, a condition called "frozen shoulder." In serious cases, the rotator cuff tendons can tear, which may lead to prolonged weakness and pain the shoulder.