Your throat tickles, you cough, it tickles more, you cough more – and the physical cycle builds. At the same time, you cough, it annoys you, you cough, you focus more on it, and the mental cycle builds. Sleeping just breaks the cycle. OR, when you lie down your sinuses drain a little differently, or in your bedroom you are farther away from the source of the irritation (if it is allergy related). There are a lot of possible reasons…