I got a weird hole in the roof of my mouth, what is it?!

As long as I can remember it has been there, it is a small hole about a thumbs distance back from my teeth. I have always thought it was normal and some sort of connection between my nose and my mouth. It feels as if i can pull mucus out from it and I think i might have gotten pieces of food stuck in it before. Its very small and when my throat gets sore, it also gets sore.
Does anyone have any idea what it is?