I was diagnosed with hypothyroidism and put on Synthroid. After a couple of years of aching bones and muscles I started to think I had fibromyalsia. I had even seen another doctor that suggested the same. Then I came across an article about Armour brand thyroid supplements. They contain both the T-3 and T-4 hormone. Synthroid does not. They go under the assumption that your body will convert the one to the other. The article suggested that for some people, the conversion never happens. Well, I had my doctor switch me to Armour, and after four weeks I have no more pains in my muscles and joints. I was so bad that I had to take ibuprophen to fall asleep at night due to the pain. Now everything is fine. I am even starting to loose weight.