I know this is not normal because I'm only 23. I've been having this for about 3 years or more -- even when I am excersizing regularly. I have severe lower back pain (so bad I need to sit down) when I am standing or walking for long periods of time. This is standing or walking anywhere longer than an hour or so (maybe more). It usually goes away on its own the next two or two days later if I rest my back. Could this mean I have a back injury? Thanks!