I had 3 utis within 2 months that took me to the ER to have a ct scan. I've learned that you must urinate after having sex, whether solo or partnered. Sexual activity can drive bacteria into the urethra, especially when f not clean. The burning would be a sign of infection. Your doctor should do both the dipstick urine test and a culture. My infection was from E. coli which does vie from fecal contamination from yourself or environment. I had four weeks of antibiotics.