I Have Chronic Sinuses Post Nasal Drip For About 7

I have chronic sinuses post nasal drip for about 7 years now. This has been accopanied with headaces that last several days at a time. I have seen two differnt ENT speicalists in the last five years they both prformed CT Scans with very little findings. As dissappointing as it gets the last ENT Doctor said he didn't know what was causing the problem and called it stress???
I am 55 years old male with Ulcerive Colitis taking 6x 800MG of Asacol per day which has been undercontrol for the last 3 years.