Maggie was doing this A LOT a few months back. I was really nervous that she had Kennel Cough or something. I wanted to get it taken care of ASAP because I knew the cold weather was coming and if she did, that wouldn't help. PLUS, I was told it could turn into pneumonia. Our vet is our neighbor and a friend of ours so we took her in the next day. He said I did the right thing by bringing her in but there's nothing to worry about. he said that it's common for Yorkies to do this because their trachea is more of an oval shape than round. Search on the internet a little and I bet you can find something on it. Hopefully, that's all it is..I'm sure Daisy will be fine