Will Radiation For Prostate Cancer Cause Urinary Infection?

I'm 60 yrs old, had brachytherapy for prostate cancer in June. Approx. 3 weeks ago (9 weeks since radiation) I have been having great difficulty beginining my urine stream. The urgency to go is great, but especially at night I cannot start the stream. My anus seems to contract and spasm while at the urinal. Eventually a dribble will ensue and minutes later I'll feel releived. This is very uncomfortable for the duration but no lasting pain following. I'm usually back again an hour later, throughout the night

Initially, following the radiation, I was prescribed Flomax. That was changed about 8-9 weeks later, by a Urologist, now I'm on Trospium Chloride 20 MG once a day, andAlfuzosin HCL ER 10 MG once at bedtime.