What is the best OTC pain reliever for severe back pain? ?

Idk what in the world I did the day before yesterday but all of a sudden the lower right side of my back where that dimple is started hurting REALLY bad! The pain has been severe and constant since then and I can't move or bend over without pain shooting through my back. Please help!!! I've got important things to do and I can't let back pain stop me. So what is the best OTC pain reliever for that? Aleve? Advil? Tylenol? Aspirin? BC powder? And how much should I take? I know im gonna have to take more then the regular dosage or else it won't do anything but how much is too much?