constant clearing of thoat

I have asthma and was prescribed Advair, ever since then I started to have to clear my throat. Ive had it for 11 months now and it drives me ,my coworkers and family crazy. It happens all the time. I told my doctor that this started happening ever since I started to use advair, and he said that advair can be the cause and that I should rinse my mouth after every use, but now it happens even when I don't use it! My sister has the same issue, she said the throat clearing started after she got sick with a cold, and ever since its been non stop. I wonder if this is a new Illness going on that no one knows about yet???