Coughing up brown phlegm for years

[drearydragon]

In eary middle school I went about a year being unable to breathe through my nose. I refused to blow it because any time I tried I would cough or sneeze. I was never really made to blow my nose as a child either. Some time after my nose cleared up I began coughing up brown plegm every morning. I am now almost 24 years old and this is still going on. I went to the doctor several times in high school about a cough and I was always diagnosed as having bronchitis. The antibiotics never cleared up the brown plegm. I mentioned the plegm to the doctor one time. He asked me if I smoked, I said no only marijuana on occasion. He said (without looking at anything) that I was probably allergic to the marijuana and that if I stopped for at least 6 months it would clear up. I never did quit smoking although I started to do it less as years went by. When I was pregnant at age 21 I quit for that period of time but the plegm was still there. It is thicker than most normal plegm would be. I have tried searching online for answers before. I read about some kind of fungus that can cause the plegm but I never took action to even see if that could be the problem. Any ideas?