I have exactly the same problem but I am getting better.
My nose used to get choked in less than a minute and I had mucus developed very quickly. When I was 14 yrs old I got myself operated to get my adenydes(some internal skin) skin removed. After that it was a lot better. And now I have exactly the same condition that you have described.
However I have improved on this condition in the past one year but have not been able to eliminate it completely. I am doing regular cardio and weights exercise everyday. I jog for 10 mins daily at the gym.
For the last two months I have also started the blood group diet that you can easily find on the net.
I have been getting better and I am quite optimistic to get rid of my mucus problem which also hinders with my professional communication.
If you know some good advice that has helped you please let me know.