Answer:
My husband has this problem too. I think it is because any fluid that you have in your sinuses or lungs kind of settles at night.
why do you say not allergies? an allergy will indeed cause such symptoms. Try taking an antihistamine before bed.
i get the same thing. you should make sure that you have a fan or open window or something to make sure your room isn't too stuffy. also, consider getting a humidifier and maybe get some vicks vaporub and put some under your nose, which will help you breathe better.