I know she has had some pretty serious issues related to her implants in the past, but IIRC those were related to sutures/incisions healing incorrectly.
I'm sure that the weight of her implants can cause breathing troubles while laying on her back, just as I am sure that they do for any other woman who has even modestly big implants.
As for the statement about her implants causing her ribcage to become concave, it could be true, it could not be true. I would think that to get a good counter position to this someone could ask PBD or Beshine about it and get their reaction. And also to remember that it was a clip of her on the Maury Show, a true masterpiece of investigative television journalism.