PR, I think I've got the same problem as you.
About 3 months ago I stopped exercising completely and noticed that my nose started to become blocked, especially at night.
I have family who suffer from pollyps and I suspect that I have now developed them. The strange thing though, is that if I do exercise my nose becomes unblocked and also if I eat it becomes unblocked too.
I'd be interested to hear the result of you going to the doctors because I reckon I might be right behind you. I have a Class One also but not flying for a living yet.