I have a mild pain in my left flank/lower back area which has been there for going on three weeks. I went to urgent care and was diagnosed with UTI. Took antibiotics for the time prescribed, the pain was a little better but has returned. It s stronger when I twist or bend toward the left, it almost feels as though the pain is going up my back, in the kidney area. I ve not done anything to injure it. Not tender to the touch. 3 weeks in and now feeling hungry, having heartburn more often. Should I be concerned... what could it be?