Belt-tightening may be good for your wallet, but it's murder on your back!!

I've been having some lower back pain for the last several weeks. Although I'm 56 years old, I've been fortunate in that I've escaped, so far, the misery experienced by folks with chronic back pain. I found this article and I just might have found the cause:

http://ezinearticles.com/?Tips-to-Avoid-Back-Pain-While-Driving&id=3318354

Coincidental with my back pain has been the drop in outsides temps in the last several weeks. I've been wearing more layers of clothing (thermals, lightweight sweatshirts, extra t-shirts, etc), all of which I've tucked into my pants. Problem is I've been using the same hole in my belt that I've been using all along. So, I think, I've been unconsciously giving my back some stress that it's just not used to. Have any of you experienced similar problems, and if you have, what have you done to try to fix them?