I do not know what the tests would show for polymyositis, and it might show a lot of inflammation, but I do know that I have been diagnosed with fibro for years. I have the same issues. And pain meds do not help.

Sorry that may be confusing. What I'm trying to say is I have been diagnosed with fibro. Regular pain meds don't work. I too show low inflammation or no inflammation, my pain is in my muscles AND joints. But always seems to be in my muscles when pain is highest. If I raise my arms during a flare, my shoulders are so sore, tired, like I've been working out all day. I have also been diagnosed with MCTD. That has overlap symptoms with polymiositis, RA, lupus, scleroderma. Doctors often miss MCTD. Steroids did help for a while. Sometimes I'm pretty sure my fibro pain might actually be the MCTD. So it might help to look for the poly, or MCTD, or ask a doc if they at least think it is UCTD.

The only thing that has ever taken this pain away is my chinese herbals. They saved my life for 2-3 years. If you cannot find an answer you might want to look into acupuncture.So far it's the best thing I've done.