Most of the shoulder pains are overuse injuries or due to constant or prolonged positioning of the arm above the shoulder. Sometimes, the shoulder pain can be a result of direct blow to the shoulder or fall Injury. They usually fall under 4 categories. Direct blow to the shoulder( Fractures, Bruising, Rotator cuff muscle spasm) Arthritis ( Osteoarthritis, Rheumatoid Arthritis) Tendon Inflammation or tear Instability of the shoulder