Puzzling Persistent Throat Irritation

[Androsynth]

I've been experiencing chronic, mild throat irritation for a few months now.  I can't figure it out - can anyone offer any insight?  

There are no other symptoms except an occasional feeling of post-nasal drip, but this PND is generally thin, intermittent, and always clear or whitish.  The volume is not enough to induce coughing, I just feel it sometimes when I swallow.

The sensation in the throat ranges from dryness to mild soreness.  Some days are much better than others, sometimes hardly noticeable.  It's generally worst in the mornings.  To be clear, I feel the irritation only in the upper back area of the mouth, not down the esophagus.  Drinking water and saltwater gargling help, but this thing never really goes away.

I've seen my PCP twice - once just this week and once two months ago.  Both times he notices some throat irritation (and a single slightly enlarged tonsil), but assures me that there is no sign of infection.  He believes that this is due to PND caused by a mild allergy to dust or pollen.

The allergy explanation seems plausible, because this all started shortly after I moved in to an apartment in a rather old building which could certainly have airborne allergens.  However, I'm not entirely convinced of allergy because there is very little nasal congestion, no sneezing or itchy eyes which I used to get when I suffered springtime allergies.

Another possibility would be a sinus issue causing the PND.  A dental x-ray three months ago showed fluid or inflammation in the sinuses, but this was right after a common cold, so I shrugged it off.  I generally don't feel any sinus pain or pressure, except for some pressure around the maxillary sinuses when I bend over (head down toward the feet).  This pressure persists for several minutes after I stop bending down. Is this slight pressure normal or could it be an indicator of sinusitis and a cause of the PND / throat irritation?  

Another possible sinus connection is that one day two months ago, I experienced severe pain above the upper left teeth, often associated with sinus issues, but this lasted only half a day and then went away completely.  Before that, I was coping with some TMJ issues, also on the left side of the face, but the TMJ problem has subsided almost completely.

Thanks for any ideas!

[Androsynth]

Thanks for the info!  I think that I will ask for an ENT referral as my PCP can't seem to tell me much other than there not being an infection present in the throat.  It sounds like sinus issues are a strong possibility, although the odd thing is that I have almost no nasal congestion - I can breathe through my nose just fine - which is normally not the case for either allergies or sinus infection.  It's very strange.  Would there be something that would cause PND / mucus to irritate the throat but not reach the nose?

I have noticed that the throat feels _much_ better when I prop up my head with two pillows to sleep the night before and when I get a full night's sleep.