In some cases, excessive use of the shoulder leads to inflammation and swelling of a bursa, a condition called bursitis. Bursas are often described as fluid-filled sacs located around the joints which lessen the friction caused by movement of the shoulder. Bursitis usually occurs in association with rotator cuff tendonitis. Sometimes the many tissues in the shoulder become inflamed and painful, which in turn may limit the use of the shoulder. The joint may stiffen as a result, a condition known as a "frozen shoulder." The good news is that with appropriate care, this condition will usually resolve itself.