For the past week I have noticed a constant sour smell in my sinuses. There is no pain, a little bit of swelling on the right side, but no odd mucus,  or icky snot. I do take flonase for allergies, which haven't been very bad lately, so use it much less often. I have heard of nasal yeast infections and am concerned if this may sound like that. I unfortunately have seen one of those amazing bizarre medical shows which profiled a man who ad a nasal yeast infection which led to him having a substantial amount of is face removed because of it. yikes. I have crappy insurance too.  I don't have any idea of what to do