I have an unusual problem for a cfer. My son who is 5 does not want to cough. At clinic when he is asked to cough he refuses. At home he does not cough. It is a puzzle to me as he use to cough. I'd hear him when he woke up in the morning coughing but lately his cough has vansished. Any thoughts? My concern is that he is just breathing shallow and not clearing the mucas in his lungs.