Even if your nose is perfectly healthy, one side is always partially closed. The turbinates open and close alternately to help clean your nose.
If you are stuffed up with no colored snot, you may possibly have an allergy--either to a substance, or to a fungus in your sinuses. Try a Neilmed Sinus Rinse at first, and if that doesn't work, try a Flip-Turn Sinus Flush, which will clear your sinuses of all allergens.
http://www.medhelp.org/user_journals/show/2322
It's a risky procedure, because you have to bend over to defeat gravity, preferably in shower, but you can also do it outside on soft ground. If it doesn't start to get results after 4 or 5 treatments, you have at least eliminated a possible cause.