Nasal Blockage

For the past few weeks my nose has been acting really weird. At first one side would be stopped up 24/7.

It has improved a bit though. Now the only time I am affected is when I lay down. One side of my nose is almost 100% blocked but will change every time I switch sides. I can feel the mucus or whatever it is moving through my sinuses when it switches too.

I started using nasal spray and it will open my nose up and all of this clear stuff will drain out and then I can breathe perfectly. Even when laying down.

The problem is that the ONLY time this stuff will drain out so it isn't blocking one of my nostrils is when I use the nasal spray.

I am a hypocondriact so I am worried it's nasal or sinus cancer.

My question is,
If I had nasal or sinus cancer would the blockage switch sides? Also, would nasal spray help a serious condition like that?

Thanks for the help!