I’m sure there’s a reaaal easy answer to this one, but I can’t think of what it might be. Water is such an innocuous little liquid. When our noses can handle all sorts of other stuff (a lot of it liquid), why is water painful? Is it because I’ve gotten it beyond my nose and into my sinuses? Even then, why the pain?
If it’s pool water, the chlorine is what causes the pain. If it is just plain water, it doesn’t hurt - although it is uncomfortable. If plain water causes you physical pain, I have no explanation for that.
Well it’s definetly not just water that hurts, try getting some vodka stuck up there some time, I botched this shot once and started laughing half way through, some of the vodka got stuck in that in between place, didn’t quite come out my nose but it was on it’s way, It hurt like a Mother for about 15 or 20 minutes. Far worse than water (even pool water) I assure you!
Most of the time when liquids cause us pain it’s because of the difference in pH levels between lachrymal fluid or mucus and the foreign liquid. If needed, our resident chemistry geeks will be along shortly to explain more about the proton donor/acceptor relationship between acids & bases.
And even plain water is more uncomfortable psycologically than it is physically, probably stemming from our deep-seated instinct to keep water out of our breathing passages. Once you can get past that hangup, nasal irrigation can be quite pleasing as demonstrated by these people.
Ever puke so hard that it comes out of your nose? Now THAT hurts like a demon.