Is it a kidney infection?

[Sam1267]

Hi everyone, I am currently suffering from some kidney infection symptoms. I recently had a UTI and was put on two different antibiotics one of them being ciprofloxacin. I have still been experiencing some symptoms of the UTI (they aren't as bad as before) such as a slight burning while I pee and an urge to urinate. However, the pee test that my doctor did came back negative for bacteria the last time I was there and they let me go on my merry way even with my slight symptoms claiming that it could just be irritation and should go away. I took some AZO and that seems to have taken care of the symptoms of the UTI for now. Currently I am having some back pain in my lower back. It's pretty dull and all around annoying, it feels like I need to stretch a lot. I am also on my period and I realize it could just be normal menstral pain as I sometimes do get. My question is, how probable is it that it's a kidney infection? I don't know if I still have the UTI symptoms because of the AZO but I'm sure once it wears off they'll be there. I've had this UTI for almost three weeks now. Should I go back to my doctor if the symptoms do not go away in a couple days?