The only lower back pain I've had is a trapped sciatic nerve. Very sharp pains my left leg for a bit but it's not always that bad. The physio gave me some stretches to do every morning which really helped. Just googled sciatica and found this:
http://www.johnberardi.com/articles/..._your_butt.htm
The intro is kind of useful but the "How to Go 'Bout Fixin' It." about half way down is the useful bit. They're the same streches I did and I was all well with in a week or so. Hope this helps!!