Swelling/pain on tip of penis

[Michael3696]

The tip of my **** is swollen ONLY on the left side and the swelling does not reach the actual eye/hole of the penis. It hurts when it rubs against my underwear, only on the swollen area which is not significantly large, it's actually a rather small portion. It doesn't burn when I pee, and I am no longer having sex with my partner/girlfriend. She does not have any vaginal symptoms or anything like that. The only thing I can think of is an infection of some sort.... UTI or maybe kidney stones? Maybe a stone is stuck there and is too large to simply **** out? I don't know. I've read other posts and to the best of my knowledge I don't have any STDs or Herpes or anything like that or at least I hope so. I have yet to visit a doctor, I was planning to wait another few days so I've waited at least a week. Is it just sore from sex? Is it kidney stones? Do I have a UTI? Remember it doesn't burn when I pee.... Unless I drink a lot of coffee but that's normal I believe, I also drink a lot of iced tea and soda which is why I thought of kidney stones.

I'm only 19 by the way, about to be 20.