My back had gotten really weak over the years. Especially in my lower back..waaaay low and then goes down into my legs. I had a few "good days" so I over did it and now my back is out...hard to walk. I may go have it x-rayed tonight. - I took an Advil- but isn't doing much good right now. Has anyone else's back gotten weak due to the Fibro? DayTrip.