I have had the same problem of not being able to get air though my nose.
I have had my nasal turinates surgically reduced and for a while that helped but for the last 2 or 3 years I have been getting worse again. I went to my ENT a few months ago and she said that the internal nasal valves in my nose are to small and also tend to collapse when I inhale.
There is a surgical proceedure that can open up those valves so I might give that a try.
I use breath rite nasal strips that you can buy at the drug store and they help some a night time.
Unlike you I also produce a lot of mocous which adds to my problem.
My chest hurts from trying to breath through my nose do you have that too. Please feel free to send as many messages to me as you want, maybe we can figue out how to solve our nasal problem.