I Have Had Chronic Sinusitus For ~ 7 Years Which

I have had chronic sinusitus for ~ 7 years which produces a lot of mucus. Over the past year I have been experiencing a cough that I can feel the at my sternum and up through my lungs above. I cough every few minutes and then the tickle in my throat and chest makes me cough hard and won't let up until i cough up the flem. Then it is calm for a while with only a few coughs and then it starts again. It is the worst when I change from up to laying down or visa versa. Should I see a doctor?