Hi there-
Am I correct that what you are trying to say is that you have a hiatal hernia? In this situation, part of the stomach tissue pushes up through an enlarged hole in the diaphragm into the chest, causing pain and reflux of stomach acid.
If this is the case, there is no reason that you should not be able to pursue a brazilian butt lift, although it is very important that your reflux be under control at the time of anesthesia.
If you have a different type of hernia, it may not be in your best interests to have a BBL, as the procedure involves liposuction, which may not be safe if there is a true hernia in your abdominal wall.
Your best bet is to discuss it with your family physician first, and if it is indeed a hiatail hernia, then with a skilled and experienced plastic surgeon Certified by The American Board of Plastic Surgery.