I ve been experiencing pain/discomfort, for a week or more but seeming to progress, in the top of my left shoulder (muscles between the joint - the joint itself feels okay - and my neck), the left side of my neck, and the top front of my left chest, as if a rib or collarbone is out of alignment. Now, even my left breast is starting to feel uncomfortable. Ive had some emotional distress lately. I remember hearing that the chest was can get inflamed with emotional distress. This is definitely only on the left side, though.