Keep reading about people suddenly dying of myocarditis without knowing anything was wrong it scares the life out me how common is it for sudden death to occur?

In the US there are: about 400K - 600K sudden deaths a year (about one a minute.) These are usually associated with coronary artery disease and previous heart attacks or from weakened heart muscles (cardiomyopathy.) Sudden death from myocarditis is rare. Unless you have a cardiomyopathy is is HIGHLY unlikely that you have anything to worry about at all.

Very rare: When the news hits the paper, it must be a rare event. If one worries over so many potential causes for death, one would not be able to live a full life. If you are healthy otherwise, don't worry. Worrying too much can cause illness by itself.