Hello Dr. : For approximtely two to three months, I ve been smelling something which is a strange combination of metallic smoke, ammonia, and vinegar. Initially I thought it was cigarettes, but i s much more acrid than that. Last December and January I did have a deep cough which I took Mucinex for, and consequently it went away. In the spring, I experienced a very brief bout of itching in the lungs and subsequent coughing.