If you have not been tested for Hashimoto's hypothyroid, I would suggest you get the antibody test done to see if you are spiking those. Hashimoto's can and does cause joint aching and pain. I have had it for over a decade. I would intermittently get joint pain while taking Synthroid. I was always in the "therapeutic window" but always felt like crap. Tired, achy, and no desire to do anything but sit and watch the world go by. All the while the endocrinologists, the supposed expert, would tell me "its not your thyroid" despite continuing to have other symptoms as well including constipation to diarrhea, thin hair, cold constantly and weight gain by looking at food. When I finally found (after three endocrinologists) someone who was willing to treat me like a patient and not a recipe from a cook book, I got started on desiccated thyroid. They drove my free T3 a little above the therapeutic window, my free T4 a to the low end of the window, and TSH also to the low end of the therapeutic window. Basically, my thyroid has a very low load being placed on it, which causes it to not have to work very hard. It seems like this also causes the immune antibody reaction to be suppressed since the thyroid isn't producing so much of the hormone that causes the antibody reaction. Consequently, I don't seem to be getting the achy joints, and random joint and connecting tissue pain any longer, at least not nearly like I used to get. In addition since T3 is really what carries the workload for your body, (T4 is converted to T3) I have more energy, and no longer suffer from the symptoms of hypothyroidism. We are all individuals and you may well be different. However, if you have been on Synthroid and didn't find it to be the medication that helps you, I would give the desiccated thyroid a real chance.