Hello I Have Been Suffering From Sinus From Past 1

hello

I have been suffering from sinus from past 1 year. initially i used to get pain in my right eye because of sinus pressure. it was cured by a course of antibiotic. after that i have got sinus infections 2-3 times. it was cured again by antibiotics.

i am not having face or eye pain anymore - which is great. however i still have thick mucus running down my throat. it happens every morning and evening or even during day time. i have done city scan recently and my ENT specialist did not find any abnormality. i also get cough because of mucus. I feel irritation around my right eye.

whats the cause behind this ? i take steam regularly and avoid milk products as they are proven to create more mucus.