I have a 7 year old large Chihuahua (18 lbs) who has always been in good health. Yesterday he started hacking and spiting out (not much). He is not vomiting, just hacking up. I checked for an obstruction and don't see one. He hacked on and off through the night and is obviously in some discomfort and as a result is insecure and wants to be held. He is still very active. He ran another dog out of the yard yesterday, so he is not lethargic as might be indicated from something poisonous he ate. Suggestions?

