Please seek the advice of a good allergy/immunologist or pulmonologist.  Some questions:  do you have a productive cough?  Are you able to easily get phlegm up?  Is the phlegm green, brown, in in small balls?  Do you cough so hard you lose your urine?  Are you wheezing, or have a history of asthma?  Chronic cough is not normal - it is a sign of underlying irritation or disease.  Your lungs can only sustain so much of either before damage sets in due to constant inflammation of the lining.  This can lead to asthma (if you don't already have this), bronchiectasis (much more serious) or pulmonary fibrosis - which is fatal.  You MUST ask the doctors to check you out for ABPA - allergic bronchopulmonary aspergillosis and to also rule out cystic fibrosis.  Don't play with your well being or life.  Take it from someone who was misled and misdiagnosed long enough with a chronic cough that I now I have irreversible lung damage and disease.  Not many doctors consider, recognize or even look for ABPA, which can be slowed in early stages before lung damage even sets in.  Insist on a CT scan of the chest; at a minimum - a chest XR.  However, be forewarned that a chest XR often can look normal with no infiltrates in early ABPA.   The best testing is the CT, IgE levels and skin testing for aspergillus.  Good luck!