What helped me was taking Flexeril (a muscle relaxer) in combination with a physical therapy by a therapist who specializes in myofascial trigger point release. I tried PT without the Flexeril and had no relief. In fact, my PT said he never saw anybody's muscles inflame the way mine did.

Once I started getting relief from PT, I began light stretching, and then moved onto light strengthening. All of this with the PT and still on Flexeril. Now, after months on abx, I'm feeling much better and can do much more with my arms and shoulders. I can even do backbends in yoga.