Mrrzy....I have a similiar problem...chronic nasal drip, gunked up back of throat, etc. Haven't a clue anatomically, but what works for me is sniffing salt water.. start mild with like a quarter of a teapoon of salt to juice glass of warm water (to dissolve the salt), then work up to whatever level you can stand. Pour some in your cupped hand and snort it (sorry, no other word for it) into the back of your throat. If you can finish off the glass this way it really clears the pipes...done an hour or so before a gig should leave you a lot clearer for the evening. This works well for snuffly colds, chronic sinus conditions, even sore throats. It IS something you want to do in the bathroom with the door closed, however! NOT a pretty sight...or sound.