I am looking for some advice on a 22 week old Yorkie female with a chronic cough. I purchased her from a pet store (yes I know

) and they told me she had been treated for kennel cough and was up to date on her vaccinations. they claimed that sometimes their puppies get kennel cough because they give them ample socialization/play time and sometimes they get bouts of kennel cough. When I brought her home I did not noice much of a cough for about the first two days. Then the cough began. We took her to the vet for a check up about a week after she came home. They gave her antibiotics for the cough and otherwise was healthy (they did not want to give the next round of shots due to the cough however). She seemed to be getting better with the antibiotics for a few week, however 4 weeks later her cough was back full force. We took her back to the vet and they gave her another round of antibiotics and a cough suppressant. They also x-rayed her heart which came out normal and said her lungs were clear. The cough suppressant seemed to help somewhat but she was still coughing. We took her back to to the vet and they gave her cough suppressant and antacids. One week later and there has been little to no improvement with the antacid and cough medicine. There is no pattern to the cough - at rest or at play, day or night it just starts. It is kind of honking yet sometimes sounds like she is congested. Sometimes it seems to get better for a few day, but it always comes back. I have researched until I am blue in the face and can't seem to anything that explains her symptoms from kennel cough, to trachea to heart. Just wondering if anyone has any advice.