diagnose me

okay folks, now is the time to realise all your childhood dreams of becoming a doctor, a nurse, a dentist or a know-it-all...

i have a very very strange thing happening to me.

there is a small section of my gum (i doubt location matters, but just in case, it's on my lower set of teeth under the right hand bottom version of the K9) that is numb. very seriously numb, right through.

it literally feels like there is a bit of my gums that have been shot up with novacaine.

i notice it intermitantly, but it becomes very obvious when i am chewing or drinking something.

and here is where i call upon the expertise of the interweb. anyone had anything like this? any idea what it might be? the only thing i can think is some kind of pinched nerve, but how one would pinch a nerve that affects that, well, i haven't a clue.