Pain in my empty heart
Shallow beating comes
Rhythimically in my heart
Preying upon my soul

The repeated use of heart in the same stanza is not something you want to do. Those used to professionally editing such things would suggest finding another word. Perhaps this:

Pain in my empty heart
Shallow beating comes
Rhythimically to tears,
Preying upon my soul.

Not the best of suggestions :-/ But it does throw out the second heart.

This is the only thing I found wrong. I applaude the challenge of writing such a poem! It was a joy to read :-)