hell, one more thing: louie simmons wrote that when doing box squat you should really arch your lower back and put your chest high. I think all this arch is actually putting more stress on my lower back. I'm not saying "don't arch at all", I just think right now that I'm arching my back and taking out my glutes too much.

I'll think about it, read his article again, watch some videos of others @ youtube, and tell you if I think it's related.