If I narrate the pain of my heart, it is a constant lament; listen to it coming from each of my bones just like the sound of a reed flute.

The poet speaks of an agony so consuming that it has physically hollowed out his entire being. Just as a reed flute (nay) weeps plaintively when air passes through its pierced hollows, grief has worn the lover down to his bare bones, turning each one into a vessel of sorrow. It is a striking, haunting metaphor where the body itself becomes an instrument that constantly plays the tune of its own heartbreak.