Pain in left shoulder (especially painful when i reach behind to fasten bra ). knotted muscle in muscle above shoulder blade and pain in left side if neck when turning head?

Rotator cuff: It could be your rotator cuff, which consists of a group of muscles involved in internal and external rotation of the shoulder. Some of these symptoms can radiate to the neck. However you need to be examined by a physiatrist to determine if it's actually coming from the neck or shoulder, or if it's trigger points, all of which are treated differently.

Neck or shoulder: Pain in scapular area or between neck and shoulder is likely coming from your neck. Pain in your upper arm that goes down the upper arm toward the elbow could be from your shoulder or your neck. I recommend you consult with an orthopedic surgeon for evaluation and treatment options.