Tram flap problem years later

7 years after Breast Cancer, Mastectomy, reconstruction & tram Flap surgery, I am experiencing tight, wrenching pain when bending over during yoga. Sometimes it is on the right side (where there is a large visible bulge when I lay down and lift my head) other times it is directly under the breast area near the sternum. I have had 2 doctors  (my Oncologist & a surgeon) tell me it looks like a hernia. The surgeon ordered a cat scan with contrast and that awful tasting barium, and now reports he sees no evidence of hernia, and no other testing indicated. So I am back to sqaure one and out of pocket expenses are rising with no firm answer for what is causing the pain. My original plastic surgeon is not someone I trust as I was never satisfied with the scarring afterward or his follow up on questions I had. I realize that diagnosis is difficult for many doctors but how can you dismiss obvious problems like viselike pain, by saying it's not a hernia, so it must be nothing of concern? That does not make sense. Is there anyone out there who is able to help me with this?