Teeth?!?!?!?!?!?!?!?!?!?!

Teeth?!?!?!?!?!?!?!?!?!?

I was flossing my teeth today and I noticed that there was a little bit of blackish stuff on one of my back teeth. I picked at it a little and a tiny bit came off but not all of it. What is this? Is it a cavity? I've never had one before and I brush 2-3 times a day plus floss so I'm not sure how that could happen. Also on the other side of my mouth, when I bite down hard, it is sore. Any ideas to what either of these could mean??? Thanks!!!!!!

1 month ago
I am 15 years old and the last time I saw a dentist was not even a month ago and he said my teeth were perfect and healthy.

I think that the black stuff could be plaque. No matter how many times you brush and floss, it all depends on where. I know some people that don't brush the back of their teeth and get what you do. There is a way to solve this problem. A visit to the dentist. He/She can clean up the plaque. You will then have to take care of your teeth a little bit more than you do and this problem won't come back. I am not so sure about the other problem you have but a talk with your dentist will help.