Well sometimes it happens when we eat spicy food and don't drink enough water. I had that once.... I know how you must be feeling.... drink lots of water that will help.
1 tip: after eating spicy things if you want to get rid of the burn then put a piece of bread in your mouth that will calm down the burning sensation in few minutes. Never eat sugar when burning sensation happens. That just wont help.

Hope this helps.

scgreenthumb is talking about a piece of pepper caught inside the piercing...similar to the way a piece of pepper gets caught between the teeth and gums, spreading its liquid fire around the tooth, I imagine. I have no piercings, but I've definitely heard others mention this fun little occurence.

Josh