This is by far the most common shoulder problem I see. As you can see in the picture, the long head of the bicep tendon has to curve sharply as it enters the shoulder. This is one of the only tendons in the body that bends at a sharp angle. It probably explains why people get irritation and swelling on the portion of the tendon that rubs on the "corner" of the shoulder. This causes a sharp pain in the front of the shoulder. The pain can radiate down into the bicep muscle and occasionally into the forearm.
These symptoms can be relieved with a bicep tenodesis surgery. This is an arthroscopic surgery that fixes the damaged bicep tendon to the humerus so it can no longer rub and cause pain.