Which is the greater punishment: the hook or the hunger? Why?

The hunger....

“The punishment of the hook is nothing.  The punishment of hunger, and that he is against something that he does not comprehend is everything.”

Santiago is honoured to hook and fight the great marlin.   I'm going to say the hunger might be more painful. Santiago seems to identify with the pain of the hook, it seems to drive him further to his quest. His battle with the marlin reminds Santiago of who he used to be and who he is, at least for one more time.