Ever since I can remember, I've had a small hole in the roof of my mouth. You can't see it, so I'm guessing it's the width of a needle. When I'm sick, it always becomes sore. Almost everyday, mucus passes through it, but I'm use to that. I went to my doctor once with a cold and told her about it, but she said they don't exist and didn't bother checking my claims. Is this normal? And what is it?