Medication for back pain?

Okay I'm 16, a female and I'm in serious desprite need of medicine. I have lower back pain all the time for 2 years. I've have hundreds of X-rays and MRI's found nothing so diagonosed me with lumbago. So medicine I've tried that don't work are: naproxen, ibuprofen, Tylenol with codeine, Tylenol, muscle relaxers, Aleve, bayer, BC, Tylenol extra strength. I think that's it but I'm sure I've taken more. The only pill that has EVER helped my back pain was lortab. I've only taken 1 painkiller in my life and that was lortab when I went to the ER one time. Also no chroprators no acupuncture. So pain killers only option since doctors don't want to find out what's wrong? And the pain Is extreme guys. Like so bad I would pay someone to knock me out so I don't have to feel the pain. ): PLEASE HELP ME!! also doctors appointment tomorrow to get me some medicine. Just want a heads up on what I should get. Thanks!