YES ! I know why !!! I've had the same thing. I think you have sacral/pelvic dysfunction. Did you ever fall on your butt ? Or give birth ? Or twist and lift? Go to this website: http:www.Kalindra.com - called Sacroiliac Resources. Also, I was JUST diagnosed with spina bifida occulta - missing part of L-5. I also have a tethered spinal cord - at S-3. Please read about these things. I do not know if they are connected to the pelvic/sacral dysfunction. I also have a diagnosis of fibromyalgia - by a board-certified rheumatologist. But please remember this is just a name that some doctors thought up to call a bunch of symptoms that they did not understand.