Lisa
This is going to sound strange but... I teach weight lifting and my form during training is very good. Last November I thought I had torn the sub-scapularus (muscle under the shoulder blade) because the pain was so severe. It was like a triangle of agony from the top of my shoulder, next to the spine at T2 and then under the scapula. The pain radiated all the way down my arm - I almost wondered if I was having a stroke! It took two doctors before they figured out it was a pinched nerve at C5 - C6. If it could happen to me, it could happen to you. Treatment will vary from person to person, for example, physical therapy made mine worse. Ice helped and anti - inflamatory drugs - perscription ones and when the swelling went down a bit, chiropractic care. Let me know how it goes