although it is quite possible to sneeze with a cold, it sounds as if it is allergies. you sneeze b/c something is tickling the inside of your nose(so to speak) so it could be sinus, which goes hand in hand with allergies. the mucus in your nose is runnig down the back of your throat while you are asleep which makes it sore. when you wake up it eventually goes away. you start sneezing as well b/c of that same mucus. im far from a dr., but thats what it sounds like to me.