According to Osho, your heart is not malfunctioning; love is dissolving the inner 'I.' This is the great death—ego effacement—where one feels neither breath departing nor death arriving as the self dies within. The pain comes from clinging; when surrender is total, pain ceases. Let the heart be lost; what remains is the immortal, and love leads you to the Divine.
Your heart hurts because the little ‘me’ is melting so love/God can enter; stop gripping and the hurt fades.