What Causes Extreme Bloating With Fluid Retention In The Body?

My friend is 60 and she gets attacks of severe pain. She gets extremely bloated and cannot urinate during this time. She cannot eat or drink at all when this happens. Actually she cannot get fluids out, unless she makes herself throw up. She also gets extremely thirsty when it happens. She gets pain near her breast bone and it radiates into her back. No fever, no constipation or diarrhea. What could this possibly be? She had her gall bladder out already. She has had all basic tests. .. shows irritation of her stomach lining. They have looked all though way to almost her pancreas and cannot find anything. Any suggestions? She s been on acid meds for along time, muscle relaxers (as it almost seems to spasm), and cholestyramine powder. She takes pribiotics, as well.