Do you smoke? it could be a condition called COPD. or a more healthier way of seeing it could be Allergies or the climate of the air you breathing. Coughing is not a disease in itself, it is only a symptom. If your cough is non-productive, that is you are not coughing up phlegm, your cough could be a smoker's cough, or allergy, or throat irritation, among other possible causes.