Amazing ,at last I have found a thread where a condition is described that is so close to the condition I have suffered for 4 years.I have never had problems until 4 years ago when several things occurred that could have caused my condition (which is a continuously blocked sinus and dodgy digestive system). It started after (a) a hospital visit when I had nernia repaired, but during my stay in ward someone soiled their bed and was left for 1 hr whilst we breathed in this awful smell (b) Just before I went in to hospital I asked for and was given Antibiotics to try and clear a seriously infected tooth (c) A visit to dentist,just after leaving hospital, for root canal treatment on tooth. I believe it is one of those 3 things that sparked this all off. Which one I am not sure.

Infact the first thing I noticed was my eyes feeling strange
as if I was "stoned" from smoking marijuana (which I havent smoked for decades !) That eventually changed and disappeared and have been left with continuous infection of sinuses with nasal drip down back of throat at night (and during day as well) and blocked ears that are full of a liquid (presumably mucus) .I just cannot clear my eustachian tube despite all efforts. I am now again trying probiotics and also still using neti pot etc etc. If I find cure will let everyone know.
I WAS going to try inhaling probiotics but after reading thread I ingested them instead. I MIGHT though try something like a proper organic probiotic yoghurt I know and put that up my nose using cotton buds as that has plenty of friendly bacteria. If that works will let you know.