In fact, the last time Luffy was shown to be in pain was back in chapter #1045, when Kaido bashed Luffy's head through the skull dome of Onigashima using his Ragnaraku attack. The Five Elders May ...

and the second was to slow down Kaido until Luffy returned to the battlefield. Had Yamato not taken this stand, the battle within the Skull Dome on the Live Stage would have taken a drastic turn ...