Why Is my NOSE ALWAYS CONGESTED?

my nose has been congested for as long as i can remember, its been there all my life. my Symptoms are: Dry mouth, hard to breathe, sometimes one nostril gets blocked and then that nostril unblocks and switches to the next one, but i can still breathe, my sense of smell is not that great. And i have been using nasal spray for about 4 years but it has gotten worst because of it.Someone can explain to me what can it be??? (i know it's not allergies forsure)