Idioms 2.

Aching heart: feeling of sadness or pain that one has when love has been lost or has faded.
Eat one's heart out: feeling negative emotions like jealusy, anguish or bitterness about something.
Follow one's heart: to do something according to one's feeling.
Have a heart of stone: to be cold and unfriendly; showing no sympathy to others
Heavy heart: a feeling of unhappiness or being weighed dowm with sorrow (very sad, sadness).