Pain in Anus at times. Be the problem?

Dear Doctor, I have pain in my anus or may be Prostate gland. The pain comes and goes. I went saw Urologist. He checked my Prostate and penis. He asked me to do Urine culture and semen culture. In the test E coli was found in Urine culture and another infection by some name Proteus morabilus in Semen culture. He gave Antibiotics and Alfoo 10mg. After a month I checked again both the bacteria were present. No improvement. He again gave me another Antibiotic with Alfoo 10 mg. I have completed the dosage but still paining if I pass Urine late. I don't pass Urine often as I have less water. Only in winter I pass Urine often. Doctor Urologist has not asked me to report again. Now that I get pain inside anus. What could be the problem? I don't have constipation problem, never had constipation problem in my life. 2 years ago I was diagnosed with stomach Ulcer and 1 year ago with piles by Gastroenterologist. I was given medicine and I became alright. Now again anus pain. Clarify