I can't shake this ache I carry (джен)

Ah, there it was again. The all-consuming, gnawing pit of anxiety in his stomach, how he had missed it. Against his will, Loki's whole body tensed up at the question and even though Thor could be the most oblivious person he knew at times, he could tell his brother noticed. The trickster took a breath in and sat in the chair opposite to Thor, posture stiff. The king sat as well, slowly and looked at Loki with a concerned eye.
"Is, ah, something the matter, brother?" Thor asked, tone a tad wary. "You seem troubled."
Loki was silent as he gathered his thoughts and attempted to sort through them so he would make sense. "...When we were on Sakaar, do you recall the man you were brought to? After you were captured by Valkyrie?"