Massive mucus and draining, even after cold

Hi, I'm new here, I have been having this massive mucus problem that wont go away,causing constant coughing, and since this mucus has been draining for so long it cause severe cold and bronchitis. Now that I am over the cold and stuff the mucus is still there and its starting all over again. I have tried every allergy pill known to man and nothing worked.

I have not had this problem, but my son always did...he had to have skim milk and no dairy unless very limited. The fat content in it would cause a huge production of mucus, and kick his asthma into high gear.
Hope this helps... good luck