I am not expert, but one thing comes to mind...Deviated septum. This refers to the tissue (septum) that separates the two sides of your nose. The deviated septum makes one of your nasal passages smaller than the other. You can imagine how that would create a perfect situation for one side to always be clogges. I believe that a minor surgery can fix this situation...Hope that helps.
you need to be seen by an ENT to determine what the cause is, that will tell you whether it can be fixed by an operation. Deviated septum, overgrown turbinates (which are in your sinus cavities), chronic allergies, all can cause similar problems. You would have to have a full workup and either a CT scan or scope of your sinuses.
I had a problem with stuffiness for years that was getting worse and went to see an ENT doctor and he performed a procedure in his office where he burned some of the tissue in my nose (he numbed me first of course lol). Probably the worst part was smelling the tissue burning. But once the scar tissue healed, I can breath a whole better than I ever could. If you don't have an underlying cause and it's just tissue swelling causing it, they might consider doing that. It was worth it for me by far.