Why does Oedipus say that Apollo has laid this agony upon me?

Oedipus attributes his suffering to Apollo because he believes that the god has orchestrated the tragic events in his life as a form of punishment or fate. In the context of the play, Oedipus is grappling with the consequences of his actions, which were foretold by the oracle, and he sees Apollo's influence as a driving force behind his tragic destiny. This reflects the theme of fate versus free will, highlighting Oedipus's struggle to understand and accept the divine forces at play in his life.