What Causes Sinus Pressure,throat Drain,eye Pain And Runny Nose?

I keep getting what i call a almost firm mucus snot clot in my right sinus, that cuases runny nose, throat drain, coughing, eye pain, sinus pressure and slight fever. In a few days i will sneeze and dislodge it and blow or inhale and swallow it. Then all the symptons go away and in a day or so im fine. Usually 2 a year but had five already. The clot that comes out is real firm mucus the size of a dime to nickel.