Hi
First, let me say that I am not a Doctor. Your daughter's symptoms sound errily similar to mine. I went to all kinds of Doctors for 2 years before I found out that I had severe scar tissue on my lungs as a result of double pneumonia that I experienced a few months before I had that "bubble" pain around my heart. When I took a deep breathe or yawned, I would experience that feeling. The shortness of breathe would come following heavy exercise or a climb of the stairs. I am a 54 years old Male and I had double pneumonia when I was 50.
I dont know if she experienced this illness but I thought I would mention it just in case I might strike a nerve. They treated my condition with surgery, a procedure called thoracotomy with decortication.....(I am not sure of the spelling)... It did not fix the problem. They now are treating it with pain medication that masks the pain but does not fix the problem. Be very careful of the treatment that the doctors prescribe. I am now "hooked" on pain medication that I am currently trying to wean myself off.
I hope this helps. I just read back my response and I did not offer much in remedies, but maybe I helped with what caused your daughters' pain.