For those that feel like they can't breathe/are terribly uncomfortable in masks, they should be evaluated by a physician. This is not normal, but some people do have mask-related anxiety which can cause these feelings. It's important to sort out what is wrong - whether the issue is physical or mental. The anxiety can be overcome by a number of breathing and visualization exercises. If the problem is physical, such a lung problem, this probably would make you a candidate for severe Covid disease and possibly long-term effects, so it is more important that you find a mask that actually works for you or somehow otherwise reduce your risk as much as possible.