Why does one nostril get clogged?

Well, isn't that just a happy little question! Sometimes, one nostril gets clogged because of increased blood flow to that side of the nose, which can happen due to changes in the weather, Allergies, or even just lying on one side for too long. It's all part of our bodies doing their best to keep us balanced and healthy. Just take a deep breath, maybe try a warm compress or some saline spray, and remember that this too shall pass.