i know i fight a lot with my sister but not hitting on skin contact that for sure, anyways, i had it a couple of time for awhile. My mother claims that i must been sleeping on it too long during my sleeping hour/naps hours that's not the case. I know what i do and today i been going shopping and etc, maybe i pull a muscle or some sort? it hurt when i try to stretch or bend over it, I'm 16 and it started since i was 14 too. i hope its nothing too serious if it is then i don't want to worry my mother either. please tell as soon as possible, yes i also carry heavy stuff and i do sport such as wall climbing during school day at gym everymoring after breakfast plus I'm overweight since i need to lose the fatty in me (lol). and plus i carry my 5 year old cousin as well.