Hi, I Am 33 Years Old Male. I Am Feeling

Hi, I am 33 years old Male. I am feeling pain and burning in urinary bladder, Doctor has tested urinary sample no infection found and they did send for culture but still not found any infection. The Dr give me antibiotics for suspected UTI. Although symptoms improved but they did not go away. I already took the antibiotics for 30. Again Dr advised me to take another 15 days. Any advice would be appreciated.