Here are the two files you can print to create a face-mask exemption tool. Store managers and the like will tell you face masks are "ordered" by the county, but if you look at your public-health officer's published document (search for it under COVID-19 on your county website) you will find that you don't have to use one if not medically tolerated. That, by the way, includes feeling like you can't breathe: hypoxia (oxygen deprivation) and hypercapnia (CO2 re-inhalation) may result as a consequence of not being able to breathe properly, and both are bonafide medical conditions. Download the image below (click for enlargement and then right click to save) and print out. Laminate. Carry with you.
For a durable DIY home "lamination": print the two files below (drag them into a Word doc and make them smaller if you like), paste onto both sides of a piece of cardboard, and wrap in clear packing tape. The final effect will be sturdy and water-resistant, depending on how much tape you use.
Click on images for front and back of card