I think you're sore because you helped your brother move. Are you saying you had intercourse after oral sex and used a condom during that time? That's very smart of you to do. I would recommend using a condom during oral sex too because if a girl, or a guy, has oral herpes it can be transmitted through any kind of oral sex. Chances are you don't have it because you would have probably noticed mouth sores at some point if you've known this girl for awhile. It's smart to be tested, just in case. But please remember what I said. Use a condom during oral sex and intercourse every single time. I think your test will come back just fine.
You really don't need to get tested. You used protection and oral sex isn't really much of a risk and no risk at all for HIV. As for your groin pain, that's not really indicative of getting something from sex. Sometimes when a man is hard for a long time you can get some groin pain. It goes away. And the other things you do might have caused some strain. It's always up to you whatever you want, if a doctor will give it to you, but what you did is pretty safe. As for using a condom for oral, you can, but neither of you will like it. Latex isn't the safest thing to be putting in one's mouth either. But there was a time when this was recommended early in the HIV epidemic, but not much anymore. Yeah, it's possible to get something, but it's possible to get a lot of things from sex, including the flu and covid. There's no perfect world out there that's 100% safe but I don't think this is something you should spend time worrying about. So you have two opinions, and you can do some homework and then make your decision. Peace.