Question: have cough that won't go away?
Answer: An infection. If your cough did accompany a cold, pneumonia, or the flu, keep in mind that it can linger for a while after the infection has cleared. ... 
Chronic obstructive pulmonary disease (COPD). ... 
Asthma. ... 
Postnasal drip. ... 
Cystic fibrosis. ... 
Gastroesophageal reflux disease (GERD).