Asthma is caused by inflammation of the tubes that carry air in and out of the lungs; these tubes become sensitive and narrow temporarily. This can cause wheezing, breathlessness, a tight chest and coughing, symptoms which become more severe during an asthma attack.
This is a companion discussion topic for the original article at https://patient.info/news-and-features/common-asthma-inhaler-mistakes-to-avoid