For the past week, it started in the left back shoulder blade and was there for only one morning, then moved down into the top of my left arm. seems like the underneath side and it is a severe throbbing, aching almost unbearable ache. I try to describe it as "a severe anxiety attach:" as it is most painful in the morning but is not solid throbbing, almost pulsates. i cannot put a finger on the exact point of pain...I am 50, in very good health i guess but i havent strained or anything like a muscle pull. I take aspirin and it lulls it but does not do anything for it. Help please