sore or pinched nerve?

[meganbmoore]

The last two days I've had what feels to my tongue(too far back to see) like a canker sore behind my wisdom tooth.  Because of it, it's hard to open my jaws very wide and I can just open them wide enough to eat...anything else starts hurting too much.

Anyone else ever a sore there?  I can't tell for sure if it really is just a sore and will be gone in a couple days, or if it's a pinched nerve or something, meaning I should go to the doctor(dentist?  Not sure which it'd be, actually)