Are you sure that isn't teeth grinding.. something they do when stressed/nervous?You can hear his breathing well in this video. He also sounded like he coughed or sneezed right after I stopped recording. When he is just setting in his cage he doesn’t make this noise as often or for as long.

Are you already offering a timothy based pelleted ration with stabilized C, plenty of timothy or grass hay, And some fresh vegetables?
They, like rabbits, need to consume their cecal feces I believe.
I love guinea pigs!

ETA: Oh gosh, it does sound like breathing when I turn it up. If so I would seek veterinary care.. since I think I read that WAS a possibility.
