I am not a researcher, so I cannot say if we are born with what we say is having a heart. Maybe Babies hearts are filled with what is put into them from the people around them, in our society I know that baby animals, baby humans have the ability to instill joy and care and love and protection from humans almost like nothing else.
Personally, I went through a time when it seemed my heart had stopped. I think it happens when you are feeling so much pain yourself that your body or emotions cannot cope with anymore input whether it is joyfull or painful. The good news is that it does pass.