Hello all fellow Yorkie lovers. I adopted a 3 month old puppy 2 days ago and I love her!

However our story isn't going as planned. I took her to the vet today and informed them of her cough, sort of like honking at times sniffling, chocking or throwing up.

They told me that her physical was A ok but if I was worried they would go further and take an x-ray. I said yes to the X-ray as I am very worried for her well being. When the Vet came back she informed me that her heart looked larger than normal but not other symptoms of having a heart issue is evident.
I am not sure what to do at this point since the breeder doesn't want to do the ultrasound I may have to do one myself. I just needed to get to the bottom of this issue which I thought was a collapsed trachea but instead the X-ray showed an enlarged heart. Does anyone else have this issue or have gone through this issue? Please help!