I am a medical assistant. I would say probably a urinary tract infection or a bladder infection. Pretty much the same thing. Does it hurt or burn to urinate then that is probably what it is? If you are itchy there and it burns then it probably is a bad yeast infection. The only way to really find out is to see a doctor. You will need an antibiotic to get rid of it. If it itches I would go buy an over the counter yeast infection cream like Monistat that should help if you don't go to the doctor. But I suggest you be seen in case you do have a uti. If your back aches you may get a kidney infection with it. So be careful and get seen. Take care and good luck.