About a week ago, I noticed a slight painful burning when I peed, I figured it was a UTI, because I've had one before, and it went away. There was also a slight pain when I had sex with my boyfriend. Now, there is irritation in my vulva/vagina, sex is painful again, but there is no discharge or pain when I pee.
It's just kind of like, what the heck? Could it be yeast, minus the yeast, or some other kind of vaginal bacterial infection?
Is it possible to have both at the same time?

Yes, it is possible to have both at the same time. Would it be possible that you have contracted an STD?

Either way, it is necessary to have this checked out by your physician.