Coughing that is worse at night is a helpful clue. Certain conditions are worse when lying down for example heartburn and esophageal reflux of stomach contents. If you feel stomach contents, vomit or heartburn in your throat, day or night this sign is very suspicious hoarsness in the morning this could also suggest esophageal reflux.
Asthma is also a disorder that commonly gets worse at night even in mild cases. Anyone may be susceptible to asthma with a personal or family history of allergic conditions(asthma, hay fever, allergic rhinitis, hives, or atopic dermatitis) or any history of chronic exposure to cigarette smoke. Daytime exposure to allergens and irritants(e.g. smoke)may not cause dramatic symptoms during the day however when you settle down at night the asthma and cough worsen. Also at night the anxiety over coughing is magnified by interrupted sleep in you or a partner further magnifying the porblem.