back pain is usually only associated with a UTI if the infection spread to the kidneys, but i'm pretty sure if that were the case you'd have a fever and more intense symptoms. if there is no burning when you urinate, or intense pain directly after urination, then it is probably something other than a UTI. if the abdominal pain feels like cramps, then that's what it probably is. but if the pain occurs after sex it may be due to him going too deep and hitting your cervix during intercourse. also, how long have you been on birth control? different types of bc have different effects on all women, especially in the first few months while your body gets used to it. that may be the cause of the abdominal pain, but if it is really severe i would definitely talk to your doctor about it. if the pain isn't bad then i wouldn't worry too much about it, as both back pain and cramps are symptoms of PMS. also i believe that certain types of bc can cause frequent urination. you might want to research all the different side effects associated with depo-provera. Hope everything turns out well.