Hi, In midnight, around 1 or 2 clock, i get cough suddenly. i feel something poke or sharp in my right side throat. the cough will be unstoppable. to stop the cough i drink lot of water. it happens only once that too at midnight. few days in a month or couple of months i get it. i have this problem since my childhood. others tell me that i use to sleep with my mouth open. but not all the days. why is this happening and how to cure it.