guinea pig coughing/choking

Question
our 4 yr old guinea pig seems healthy except that he will occassionally make a loud coughing sound, as if something is caught in his through and he is trying to clear it.  It almost as if he sometimes eats too much and can't swallow. he also sometimes makes the sounds as when a person has congestion & needs to cough to clear their throat. this goes on a short time & then he makes the coughing sound and he is fine.  at other times, it seems as though he does it just to attract our attention.  

should we take him to the vet, even though besides this he seems normal. I have looked online & know that if guinea pigs catch colds it could be dangerous to them, but i don't know, since he does act healthy in all other respects. (what are the symptoms for a guinea pig with a cold? allergies? could something be wrong with his back teeth?)
Other background info if it helps: We have been doing construction in our house & there has been lots of dust, also.  he just had an annual exam probably about 6 months ago and he was fine.

thank you so much.

Answer
No, this is not something you need a vet for. That noise is common in all pigs. You may not have heard it previously but chances are it's happened and you just weren't there. It was explained to me by a vet friend that it's much like a dog with what they call a "reverse sneeze".

Having a herd of guinea pigs (68) I hear it now and then. It never seems to be anything that goes on regularly or for an extended time, and it doesn't seem to impact appetite or behavior.

The golden rule of cavies is: are they eating and drinking? When there's a health problem the appetite goes down. It sounds as though your little guy is fine, he just clears his throat now and then.