Dear marip1. Sorry no one got back to you yet. Yes, an allergist or ENT can take a look down your nose. It doesn't hurt at all, no trouble with breathing or anything. They can see if there's a blockage or possibly find an infection in one of the sinuses. They can also see if you're having throat irritation.
The maxillary sinuses open upward. I'm having trouble with mine right now. When I bend over clear fluid runs out and I'd better have a Kleenex in hand. Embarrassing. I need to get off my hinney and do my sinus washes every morning or night or both.
I love my allergy shots. I have no allergy symptoms since starting them years ago. I had to add grass a couple of years back. New allergies do crop up.
Sounds like a good allergist.