I've been experiencing this since Sunday, granted I do not take super care of my teeth, I do regularly floss, brush. Anyways, I cannot tell which it is, but it's involving my front bottom two teeth, it's not exactly 'pain', but it's sure from pleasant. In the morning it's non existent, so I'm always under the illusion it left, then in a hour or two time it's back. It only seems to be uncomfortable when I open my mouth for deep breaths, or if I do a lot of talking. Eating, drinking, does seem to affect it. I'm sure this is the sort of thing I'd check with a dentist with, but with money as tight as it is these days, I hope it's something that wont require such.