Help? I just had weird sharp pain in my lower back for like 15-20 minutes

[Teddy Obrecht]

and now its gone? what the heck could this have been. Oh yeah and im bout 13 of it helps. The sharp pain would ebb in and ebb out at time but when i lied down and then put a pillow under my back it reduced the pain. Then slowly the pain ebbed away. What the heck could this have been?