Sometimes it's from the way we're built (sinuses, etc.).
If you don't find sleep refreshing, then that's another symptom -- still doesn't mean you have it, but if it does, it's worth knowing, as things can be done about it.
And yes, I'll be the first to admit because it's something in my life, I'm probably a little preoccupied about it, and may be a little paranoid about it in others.
Anyway, you're an adult, do what you will.