I'm trying to find the right word but i can't.

What is the sound a man makes when he is in pain? Like when it's more than just a groan but he is too controlled to actually scream. (i don't really know if shout is the right word though). It's hard to explain but the scene (it isn't KPop based but i thought you guys might still help me) is basically about a really tough masculine man who has asked his friend to whip him because he feels really guilty about hurting his loved one, who refuses to hurt him and he feels like he needs to suffer. So he is supposed to be enduring it well but the pain is getting too much for him, he is restraining against crying out but it is getting too much to handle so he makes a sound. I'm wondering what word you would use for the sort of sound he makes?

It's not a scream or a cry (really), it's more than a groan, moan or grunt. Basically i'm looking for a whole load of words that might fit this description. They should be masculine sounding if possible (i know it's weird to explain but it needs to fit his character) 

(For anyone who's interested/may know the character - the man is Thorin from the Hobbit)

I know this is a really bad description but if anyone has any suggestions i'd be really greatful <3

Kamsahamnida!

Ppyong,

BabyLocket Xx