Im not sure if this is costo. or fibro, etc, but it sounds like it MAY have been caused when you injured your shoulder. I first noticed my costo. also when i stopped taking nsaids. Do you have problems eating where you feel full instantly and have nausea? Do you have muscle spasms in/near your stomach?
As for being diagnosed with fibro or costo., the best doctor to go to would be a rheumatologist. THats if you havent been to one before. IF you have, maybe try a different rheumotologist.
Im sorry you have had pain for such a long time with no answers. Hang in there and dont give up without an answer! I can definitely relate to not being able to ever go out. good luck.