What Could Cause Lower Back Pain And Burning Sensation During Urination?

I'm 57, 5'9" 190#'s female. I have been experiencing lower back pain, no burning or anything when urinating. Went through 2-1/2 days of being doubled over. Went to doctor & they gave me 7 days of meds. I'm still experiencing back pain. When I eat it get full really fast, my stomach hurts(feels like it's in knots) & wish I hadn't ate. Most of it subsides within a couple of hours. I do take Lasix for fluid retention. No problems with bowel movements. My last UA shows PROTEIN 20 (trace) & WBC 6-10 along with a trace of Bacteria. Does it sound like the infection is still there or maybe not just a UTI?