I wore a KN95 mask today for a few hours, for the first time, and my chest is bothering me now. It hasn't happened with other masks. Chest pain might be a side effect of the mask. Anyhow, I just wanted to give my 2 cents.

I read the other day the pressure needed to breath through n95 masks is stressful to the heart, and this is the reason it is better to wear the other kind and maintain your distance when out and about.