hi i have had shoulder and arm pain down to my hand and fingers. numbing and tingling in my middle and ring finger. I had aa mri done and my dr today told me that he does not see a rotator tear but he did see an accessory muscle. He gave me a cortisone shot to see if it helps any. My question is that I have limited motiona in my arm and substantial weakness. If this cortisone doesnt help wht else can be done? and what exactly is an accessory muscle? Thanks