Anyone else have this back problem? What can I do?

I work at the casino as a table games dealer, so I have a standing job. I’ve been doing this for over 6 months & my back gives me problems everyday. It starts hurting after just about an hour everyday, so I bend over a lot during the day to stretch it. (touching my toes.) Well, whenever I do that, my lower back cracks multiple times. It seems to feel a little better after that for just a little bit, but not much relief. My back does this multiple times a day (lower back) and I’m always in pain during my shift. Whenever I sit I feel better, but I am only 22 and should be able to stand for long periods. Anyone else have this problem? What can I do?