system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does my nose clog and block my air passage ways?

I'm not allergic and its not exactly pollen season, why does my nose clog up and making sleeping hard and annoying? Why does the body even have a process that blocks nasal passages and sinuses? It just seems counter productive. 

Edit: Thanks people, I learned a good amount about my nose today. Holding my breathe after pushing the air out of my lungs did help my nose open up a bit but I'll be mentioning my nose to a doc next time I see him just in case.
gpt
The inside of your nose, sinuses, and the nasal passage is covered by something called a 'mucous membrane'. Think of it like a wet carpet that has miniature water sprinklers, if you will. The function of such an arrangement is to make sure that the air reaching your lungs is not dry (which would in turn make your lungs dry, which is dangerous), amongst other things.


Come winter, and a large number of viruses find it a very conducive environment to harbour themselves in your nasal mucous membrane. These in turn cause the glands secreting the mucus (the miniature water sprinklers) to work overtime. The purpose of this is to wash out the virus, broadly speaking. But as a result of this, mucus is produced in excess. When you're awake, this dribbles down the back of your throat due to gravity, not making its presence felt for the most part. When you're asleep, it becomes difficult for this to happen. So, it accumulates and dries up. This is why you get a clogged nasal passage.


Another reason is that the miniature arteries carrying blood to the mucous membrane dilate themselves in response to the infection. This swells up the mucosa, giving you a sensation of a stuffed nose.

Not exactly the most comprehensive explanation, but hope it helps.