Welcome to HealingWell, Lisa.
I'm sorry you're feeling so bad. It's my understanding that many of the symptoms of hypothyroidism and fibro are the same, and some doctors even feel that hypothyroidism can be one of the causes of fibro.
On the other hand, people with one autoimmune disease are definitely at risk of getting others, so it all becomes really hard to differentiate.
Here are some sites you may want to check for more information.http://www.thyroid-info.com/articles/muscle-joint-pain.htm