Hello, im 27 and about 9 years ago my shoulder was injured, the pain went away that same day.However about 2 years later when i was doing incline dumbell press, my arm went completely numb and it fell straight behind (like when your holding your arm foreward only in reverse) and it felt as if my shoulder dislocated, and ever since ive noticed that something had changed in the joint, thou nothing painful. However, since yestoday ive had the felling whenever i relax my shoulder i get the feeling that its slowly disloacting even when i know thats not the case, there is some minor pain at the back of the deltoid. Any idea whats causing this?