I have chronic sinus infections. The surgery for them (scraping them) that is usually done is worthless up HERE, because the cause is entirely environmental (mold, mold, mold, mold... we have more molds in our area than the Amazon). Infections just reestablish after a few months. ((It's so nice when I get to leave Seattle for awhile, my sinus infections vanish within 12 hours of leaving W. Washington.))
Pseudoephedrine HCl (the old version of Sudafed that is behind the counter, but you don't need an Rx, just ID) is a gift from the gods. Instant relief.
Flonase (a steroid nasal spray, so it's not addictive, but not everyone can take it) is killer on reducing inflammation. Although as anyone with chronic sinus issues know, there's a BIG difference between their sinuses being full of mucus and the accompanying inflammation.