Itch?

So earlier today I was just minding my own business when I started itching down there. This has happened before and I wasn't sure if it was a yeast infection but then it will go away after like 3 days. Sometimes it only lasts for maybe an hour. And it's on the outside of the vagina on one side that it itches. And if I itch it too much it burns a little when I pee. What is this?