About 3 or 4 days ago, almost immediately after oral sex, I began to feel an uncomfortable sensation in my penis. It can best be described as a burning/itching pain INSIDE the penis towards the tip; this also makes it feel like I have to urinate. Additionally, I also feel some discomfort (a very slight ache) in the shaft of the penis and the testes (this may or may not be related).
Two days after it began, I received oral sex again, and it appears to have gotten worse.
I have wondered if this is some sort of bacterial infection, or can it simply be some sort of physical damage/irritation?
Any help is much appreciated; I don't think this is serious, but it is very worrisome!
Some background:
I am a 22 year old male. I have had only one sexual partner in the past two years, and we are in a monogamous relationship (there is no doubt about this), so STDs are not a possibility.