Fibromyalgia Support Group
You're not alone in your pain. Fibromyalgia is a condition that can be difficult to diagnose and manage. If you're trying to cope with pain throughout your body, sleep problems, general fatigue, or other common fibromyalgia symptoms, you're in the right place. The community is here for you to talk about therapies and share your challenges.

In FM, it's a primary dx for me. In others, secondary or co-morbid with RA, OA, MS, lupus, (long long long list), and many of the symptoms are similar or identical. It's why they rule out so many other things before going to the FM dx as the primary or only dx.
Consider it this way. FIbro's main symptom is "widespread pain". That also applies to about 500 other things in the diagnostic manual. So until they've ruled out the rest of the possible causes that have better names and entries in th emanual? FM tends to be the "last resort" dx of good docs, and the first resort for lazy ones.
Never fear to ask your doctors anything, btw. If they're lazy or ignorant, it's a good way to find out, and if they're not, they're much better at explaining than I am!