The main cause of most shoulder problems is tight shoulder internal rotators and poor posture.   Tight muscles cause the arm to rotate in and up causing impingement of our rotator cuff tendon.  Prolonged tightness causes inflammation, tendonitis, bursitis, arthritis in the shoulders and neck.  Stretches are the key to get rid of your pain.  Elongate the tight muscles and restore joint mobility to get your posture back.