What Causes Sore Throat And Stuffy Nose With Pharyngitis?

Hi, I have been getting sick once a month since November 2013 now. It always start with a Sore Throat and then I get a stuffy nose and a bad cough with phlegm. In January I had Bronchitis and caugh so much that I pulled a rib muscle. Ever since, I always find myself clearing my throat. Now I have Pharyngitis. When I go to bed my nose is stuffy, during the night I have a dry cough like there is a feaher down my throat tickling it, and when I wake up I have a fullness feeling in my nose and I use the netipot to clear all this mucus out. Also I cough a lot in the early AM, trying to get the phlegm out of my chest. What is causing all this?