I Get Sick So Often And I Don't Understand Why.

I get sick so often and I don't understand why. I thought it was some type of allergies but now I am unsure. When I get sick it is cold or allergy like. But the main thing that bugs me is my sinuses behind my eyes and nose feel like there is something stuck in there. I do have a little mucus that comes out of my nose but the main thing is the tightness of my sinus. It doesn't feel pressured, it just feels like theres smithing stuck in there. It also hurts when I swallow. Eventually it will loosen up and the mucus will build up in my nose. But then I will get sick with the same thing two months later. This has been going on for years and nothing helps.