question: I believe I have either a shoulder sprain or strain in my left shoulder, the same one I had a sprain in a year an a half ago. However unlike last time when a sudden jerk caused the sprain, this time I was asleep and suddenly woke up with pain running down the length of my arm, and the inability to move it except from the elbow down. Also when I stand upright with my arms down, my left arm props out and I cannot put it against my side. What specifically is causing this, as well as, is this problem related to what happened a year an a half ago?