Every body is different.
To put my management of my fibromyalgia in perspective, I should tell you about mine.
I'm just shy of 5'11" tall and currently 180 lbs. Technically, that puts me just into the overweight category.
My muscles are super tight and always have been. They have a hard, ropy texture, that has been commented upon by anyone who has ever touched my body. This muscle texture was also noted in a 1999 genetic study of fibromyalgia in families. This muscle doesn't have very much stretch to it, so I don't have very much flexibility. I've had a physical therapist call me "pathologically inflexible".
I don't have a great idea of how my body moves in space (proprioception) and my balance isn't phenomenal. I never learned to crawl as an infant, and it took me a really long time to learn how to climb a ladder or ride a bike. I still have hard time with movements that cross the midline. All in all, it makes for a hard time moving.
This year, I was also diagnosed with inappropriate sinus tachycardia syndrome.