Okay, here goes. When I do sit-ups something in my lower back goes click/pop/crunch (it's hard to describe the sound and feeling). More specifically, it's just to the right of my spine, a little bit above the pelvis and it happens on the way down. It isn't painful, just uncomfortable and annoying, and I'm a little bit worried that it's the precurser to something worse. Could anybody give me a preliminary idea of what this might be?