My vagina seems like it has swollen and hurts really bad. Not to mention it itches. What's wrong?

Uhm have you had sex lately? Maybe an std

Sounds like you have thrush which is a yeast infection.

Go to the chemist and let them know what you have, you'll need to supposit a pill into your vagina.

It does go away after a while.

Yes definitely sounds like thrush not nice! You can get cream or oral tablets. I would say the tablets are the best!