When i try to sleep i get a tickle in my throat and cough and sneeze. what do you think it is?

Possible allergy: Typical allergy symptoms are sneezing, itching, congestion and clear nasal discharge. If a person is allergic to something in the house or in the bedroom such as dust mites, animal dander, etc, this could lead to the symptoms with post nasal drip and subsequent cough. An allergist can help identify the trigger so avoidance measures can be taken and less medication needed.