I don't recall hearing chins making noises when they are hurt. They are prey animals, so they are very discrete and hide any pain/illness very well.
I've heard 4 different kinds of noises from my chins:
- soft peep-peeping noises when they are let out to play
- kacking when you touch them wrong/bug them/or a cage mate is bugging them
- the mee-mee alarm call sound that I'd bet is what your chin is doing
- the death scream - this loud 'EEEEEEEEEE' I dunno why they do it, they aren't really dying, but it sounds like they are. Everytime I check on them after they do it, they look at me like I've lost my marbles.. so I don't get it, lol.
But it's normal to be over protective. Generally just watch their food intake, water intake, activity level, poops - amount, color, consistency can tell you a lot. Also be sure to check them out once a week for any wounds, hair loss, discharge, or hair ring checks if it's a male.