Most people with fibromyalgia do have hypothyroidism and the blood tests come back as normal. There's an expensive blood test (don't know name or work-up) that will show true results for fibro patients. Ask the RA doctor about that. Good Luck
I had a similar situation of arthritis type pain in my body. I am not sure if you have this in addition to your pain in you jaw? I never had jaw pain however.
This started about 14 months after I was diagnosed with hypothyroidism. I was very achey and ibuprofen wasn't even working. After about 2 months it went away and never returned except for a short achey period a few months ago.
My rheumatologist attributes it to the general autoimmune aspect of Hashimoto's. She said it is typical to have other automimmune type problems crop up with thyroid as well. Do you have Hashimoto? It is very frustrating I know and I empathize with what you are going through.
My doc said if my problems continued we could at some point look at Plaquenil which is used in arthritis, etc. to fight the autoimmune component. I just continue to go to the rheumatologist, but continue to have random things crop up, i.e. Negative ANA, Uric acid high, positive C-reactive protein. So these are monitored to make sure they don't get worse. Find a good rheumatologist though. The first one I didn't feel great about so got another recommendation and I love my new doc.
Good luck.
The TSH of 0.585 is very normal making it unlikely that the symptoms are due to thyroid. To more thoroughly exhaust the thyroid eval, you could ask the rheumatologist to test thyroid antibodies -- they often do that anyway -- and to repeat TSH to confirm. Even with positive antibodies, would typically be reluctant to treat a TSH that is already in the low-normal range.