Can a healthy heart go into cardiac arrest or heart attack due too fear, anger, exercise, sexanxiety or any kind of stress such as: natural disaster?

Kind of. Cardiac arrest of the temporary type can occur, it is called a vaso vagal reaction, usually leads to fainting, but can cause actual stoppage of the heart for a brief time, with subsequent recovery. Heart attack can occur in a healthy heart due to severe spasms of the arteries of the heart. Are you looking to explain someone's death?
Heart Disease at 28? Not likely given your age. It is much more likely that any pains or other heart symptoms would be due to anxiety or stress and this is called a "panic attack'.
No. This is the stuff of fiction. The one situation where it might happen is takotsubo which if it is ever fatal kills very seldom. .