Help, has anyone heard of throwing up water or liquids?

I have had 3 surgeries dealing with stomach problems. I have a hiatal hernia in my stomach, and I had 2 nissen fundoplication surgeries. I was throwing up all foods. But now a year after the last surgery I am throwing up water only. I have had some medical tests and they are normal. Upper GI and CT scan with radioactive contrast. Any advice will be appreciated.