I too have had a cough and excess phelgm for about 9-10 months. Have tried everything and had all the usual tests such as chest
x-ray, ct scan, broncoscopy, etc., etc. and have been on all the usual medicines. I have discovered through some research of my own, that white foods (carbos) can cause excess phelgm. If you will try eliminating or at least cutting down on pasta, potatoes, white bread, white sugar, you might find it will help eliminate the phelgm. It has helped me considerably.