I've found these nasal rinses very helpful. There are various manufacturers. They're available at pharmacies, Wal-Mart etc.
Here is a sample

Probably allergies. Mine only run when I have oxygen on. Not sure why. Right now I'm on hospice. I'm 84 so I can't complain. On good days I like to bake. I make the most of thoses. I'm very happy that I have my children all live close by. Years ago I learned a wonderful verse. It goes like this! No pit is so deep that he is not deeper still. 😇😇

I have been using Vick Vapoinhaler. This is helping me breathing better.

My nose runs slot when I'm on oxygen. Not sure why.

Thank you Wallie stewart🙂