Thanks for the replies in advance. Just finished a/Drive stack, and also just started protein. Taking 2-3 servings of protein, one with creatine, daily. Two days ago, back started killing me. Welcome to the world of no sleep. Anyhow, it's gotten better, but wondering two things. 1) Is this normal for taking things like protein, creatine. I have read posts that it only happens with harder core things, and I have read posts that people get them while taking just about anything? and 2) How long do they last for you? I know there are things I can do to make them less painful, but if its only a couple of days I may already be past the worst of it. Thanks again.