My male guinea pig sometimes makes this sneezing/coughing sound. He's in a cage that isn't really dusty (I'm using CareFresh ULTRA which is suppose to have less dust than the normal CareFresh), with only houses that provide good circulation. He eats, drinks, and does his business normally. There are no other signs of a problem, no problems breathing, nothing. His urine is a normal color, and I think he's pooping normally (he lives with another pig, so it's hard to tell). Sometimes he sneezes randomly, but mostly it's when he's grooming himself. Occasionally I'll hear him cough a bit, but not a lot. Everything else about him is fine (except the normal cuteness factor :D).
Is that bad, and what does it mean?