I do. I've tried telling all the docs about it but they said it's just functional back pain. Meaning muscle. They are wrong! It happens mostly at nights and by morning my back is so stiff and sore I can barely get up. Then when I have my morning bm's the pain starts to go away. We even bought a new bed, but I knew it wouldn't help. It feels to me like something (intestines?) are swelling as they fill up with poop, which is putting pressure on my back or another organ, and that is where the pain is coming from. I've been to physio and there is no loss of movement and I'm extremely flexible, but still they don't believe me when I tell them the pain is from my IBS!