I am a 33 year old Male, 160lbs. About 7 months ago, my wife went in to see the doctor for a UTI. During her treatment stage for it we had sex on several occasions. About a week after, my penis and testicles began to itch and my testicles swelled up greatly. I went to see a Doctor and they did a urine and blood test also did a very detailed exam of my groin area. All the tests came back negative for STDs, but I continued to have pain and swelling, they prescribed me several meds to take care of it all. The symptoms continued for about two months off and on, seeing the Doctors continuously but they never could find anything. Finally the symptons went away but every once in a while my penis will start to itch again and there will some pressure pain at the base of the head of my penis. Any clue of what might cause this?