What Is The Grinding And Pain In My Shoulder Blade?

My right shoulder blade is grinding and popping, and the rotator cuff area hurts so bad. In my should blade area I had a sist removed when I was a child. Do you think this could be scare tissue or calcium build up? It really hurts and causes neck pain and now severe headaches. Could you tell me what it might be and what kind of doctor should I see for help?