How to cure of yeast infection ? I've had a very sore spot on the roof of my mouth for about a week now?

how to cure of yeast infection ? I've had a very sore spot on the roof of my mouth for about a week now. It hurts when I eat anything that touches it. It hurts worse when I consume strong foods like: mustard, ketchup, salt ... etc. I don't know if I just hurt the roof of my mouth or if I actually have a yeast infection. I have no idea what would have caused this but its painful and I want it to go away. Any one got any suggestions?