Hello -
What you describe could be epididymitis, testicular torsion or even an inguinal hernia. The hernia is less likely than the other two, and the former two, normally, would be more painful, but they are serious enough -- all three -- that they should be ruled out. You're not being hypochondriacal because of your concern over this: the area is somewhat vulnerable to odd problems (torsion is a really odd one, but happens fairly often and is easy to correct); epididymitis is usually easily treated as well, and inguinal hernias are fairly simple to repair. It may be none of these, but it's perfectly reasonable to want to take care of the equipment, and failure to do so can have unpleasant results. Because of the relatively low
pain level you may be able to wait a few days before having this looked at, and if it resolves on its own, great. But if it doesn't in a few days, I'd strongly suggest having it checked. If it's nothing, remember that's a good thing, and if it's not nothing, it''ll be a good thing you found out.
I hope this is helpful to you. Best of luck.