I agree, you have to have a doctor that believes your symptoms & trusts you in knowing your own body....
Can you ask for a SLIGHT increase in the dosage to see if that will help? I always start by saying , "can you just humor me and let me try/do". ?
I also have half thyroid, when I was under medicated I had the same pain in joints, spine and very tired. I went to a endocrinologist who put me on a new meds Tirosint, I'm still not right and most Dr.s do not listen or they go by the blood results, I have been on meds over 26 years and believe me it's very difficult to find a good Dr. and get the right meds, I almost went into a coma being under medicated and was told I need to be always on top of my meds, so now I have to be my own Dr. I would suggest you find a new Dr. and insist your pain is from the meds your on, because I'm sure it is even thou I'm no Dr.
Please post your thyroid related test results and reference ranges shown on the lab report. Also, please look at this list of 26 typical hypothyroid symptoms and tell us which ones you have.
http://endocrine-system.emedtv.com/hypothyroidism/hypothyroidism-symptoms-and-signs.html