running at high cadence and back pain....

I don't know if there is a relationship here or not, but I have started running at a much higher candence and now my lower back really hurts. I do lift some heavy things at work, but I don't remember my back hurting like this. It hurts when I bend down or move side to side with my hips stationary. I can still run with very little pain. Any thoughts? I hope it's not the increased cadence because my times are down. Thanks

Reed