@lilbit59 have your doctors discussed pulmonary rehab with you? Two breathing exercises helpful for shortness of breath are 1) diaphragmatic breathing, 2) pursed lip breathing. With COPD, and also asthma depending on the type of asthma you have, you likely have some degree of air trapping. Pursed lip breathing is specifically targeted at air trapping. There are a lot of resources online discussing both breathing exercises, below are a couple links discussing each.
https://my.clevelandclinic.org/health/articles/9445-diaphragmatic-breathing
https://my.clevelandclinic.org/health/treatments/9443-pursed-lip-breathing