TSH = 1.05 (0.45-4.50)
fT4 = 1.05 (0.82-1.77)
T3 = 132 (71-180)
TPO Ab = 257 (0-34)
Anti thyroglobulin = 75 (0-40)
Hashimoto's IS an underlying autoimmune disease....... and yes, it can cause severe muscle/joint pain. It can also cause edema. I have swelling throughout my body, that may or may not be thyroid related; no matter how high my levels are, it never goes completely away. My fingers swell considerably and often hurt when I bend them.
What are your actual thyroid hormone levels, with reference ranges?