I have a missing filling in my upper right canine in the back, toward
the back, near the gumline.  I also have a slight chip in the rear
back inside of the tooth in front of it as well.

This week, I started to feel what feels like muscle ache along my
upper jaw.  I only actually woke up with it in the middle of the
night, and took some ibuprofen and by morning it resolved itself.  I
got it again last night before bed, and again tonight right now I feel
it.  It did not bother me at all during the day.

I am wondering if it is possible for either of these teeth to be
infected or have issues that could be causing this pain?

I have had a missing filling once before, and when it was out it
became infected and when it had pain, it was localized right on/by the
tooth itself - aka if I squished saliva up there I would feel it. This
is not the case with either of these teeth however.

Could I be feeling pain up in the nerve without localized pain on
either of these teeth?  Could it get worse over the course of a day?
I feel it all the way back, and somewhat under the cheekbone.  Tapping
the teeth does not bring any sensitivity or dull pain.  No hot or cold
sensitivity either.

I'm wondering if I am just experiencing some kind of muscular aches
from grinding my teeth at night which are worse after all day, or if I
have an infection. Yes I plan on making a dental appointment, but just
looking for some opinions.

Thanks.

--*Rob