I am a 67 year old man, i recently had a prostate operation . however i now am no better still going to the toilet upto 8 times an hour. When i pass water it appears to have grit or sand in it, and it sticks to the side of the toilet pan. I am also having a stinging and constant irritation and pain in my groin. I am now having to sit on a rubber ring as it hurts to sit on a hard chair. What could this be ? .