Hi there...my mom had Hashimoto's and took synthroid. I don't know for certain if there's any correlation but since the destruction of her thyroid gland, she had horrible muscle pain. We used to laugh because she had a container of icy hot in every room. I could not walk in the house without her asking me to rub some of it on her shoulders, back and neck. I DO know that blood work is very sensitive and the hormone levels only have to be off by a rat hair to create symptoms...such as muscle pain, fatigue etc. (that's what her doctor told me) I often wondered if she had fibro as her symptoms seemed so similar to mine.
Wish I could be of more help...
Donna