Cold and flu is discontinued due to the ban on ephedra.
I would stop all dairy and see if that helps. In addition - you could get cayenne and lobelia from schulze. They are lung clearers. The other two specific herbs that I've had good success with for coughs are ginger and licorice. As you don't want to be supressing what needs to come out - the cayenne and lobelia are better for longer term use.
But give the dairy a try. Hot cold showers can be effective clearers as well. If not - you may want to look into allergies.