Final answer:
The story of Pygmalion is part of Ovid's narrative poem The Metamorphoses, which is not sung by any specific chorus or individual as it is a written work, not a play set to music.
Step-by-step explanation:
The portion of The Metamorphoses that contains the story of Pygmalion is found in the narrative poem by the Roman poet Ovid. This epic consists of a collection of mythological and legendary stories, which deal heavily with the theme of transformation. However, the specific part of your query regarding who sings that portion is unclear, as The Metamorphoses is a poem written in dactylic hexameter and is not structured like a play with parts to be sung by a chorus or individuals. The epic itself was likely recited or possibly enacted but was not sung in the manner implied by the question.