You need to put pure water in a clean container and then process it in some way to eliminate bacterial contamination. You can process the water with heat just like you do when canning, or use a chemical like chlorine or iodine.
That said, from what you are describing several causes come to mind. They are deviated septum, vasomotor rhinitis or nasal polyps. It sounds like you might have a nasal polyp on the right side of your nose. A nasal polyp is noncancerous, sac-like over-growth of inflamed tissue lining the nose or sinuses that can block nasal airway. Since it is the same side all the time, you might also have a deviated septum that occurs when the thin wall between your nostrils is displaced to one side, making one nasal passage smaller.
Why is one side of my nose always plugged up? Don't feel sick or anything, but one side of my nose, the right side is always stuffed up. Why?