Backache. …Thank you, Thor. Really.
On the running theme of Loki’s being tortured in the void, anyone think he was whipped, and so landing AND THEN SKIDDING ALONG on his back aggravated the wounds?
^ the door is over there thank you for crushing my heart into a bloody pulp then stomping on it for good measure
He also sort of slumped over like his back hurt at the beginning of the film when he was running and then jumping into the S.H.I.E.L.D. vehicle to escape.