I have lower back pain, odor, and creamy discharge, doc says its bv, I've taken flagyl, clindamycin, amox cal, and I still have symptoms?

It is time to Cultur. Back pain her is sequence of the pelvic infection most likely, I would recommend culture and sensevity to be done on the discharge and x-ray of the lumber spine and ultrasound to be sure you do not have problem in the spine beside the pelvic problem.
If indeed BV... That's the $64, 000 question, if you are not responding to treatment. Sometimes, antibiotic treatments may actually make the condition more frequent, recurrent or complicated by fungal vaginosis. Was a culture obtained? Please further discuss with your pcp and/or gyn.