Thought you might have just started and needed to let your lower back catch up.
I always feel something after a set of deads, but I couldn't necessarily describe it as pain. I think that if you're really hurting, beyond a normal soreness, after your deads, then it still could be a form problem. But there's no way of knowing that.
Some of the more experienced powerlifters might be able to help you; Heavywear, B Fold, one of those guys. You might try posting this on the Powerlifting board.