What the heart is supposed to do

This lump of muscles in me,
It's supposed to work.
It's supposed to pump blood into my streams,
It's supposed to be the thing keeping me alive.
Keeping me human.
What it's not supposed to do though is ache in soliditary, thinking it's strong enough and capable enough to be at the receving end of such humongous blows.
It's not supposed to ache this way.
It's not supposed to feel at all.
It's not supposed to break.
Not feel, or break.
Not feel or break.