How do you know if you have a yeast infection?

I've been feeling super itchy and it feels like it burns down there. I dont have an STD or anything. Im afraid it might be a yeast infection. How do I know and how do I get rid of it?! I have also been getting bumps kinda like a pimple down here too. Not on my lips of libia(however you spell it) like on the top where it leads to the actual vagina if you know what I mean.