How many days after finishing antibiotics does it take for uti symptoms to go away? i felt soreness go away but now it's back.

See doctor: Where is your soreness? Abdomen or back? Were you originally tested for a UTI, or was it diagnosed over the phone/by history. Usually your symptoms should improve by the time you finish your antibiotic course. If symptoms return, you may be resistant to the antibiotic, or it is not a UTI. I'd recommend seeing your doctor and consider getting a urine culture. Best wishes.