hiatal hernia, possible but I think it can be explained by other causes.
I don't think that it would stop the supplements from getting to your stomach because that is not what hiatal hernia does. It just causes a large opening which can cause reflux. There are other causes which are more likely. I used to have reflux many, many years ago. It diminished, probably because my stomach acid levels dropped even further. You might still be at the point where it all gives symptoms of reflux. If left it could stop entirely due to even further lowering of your stomach acid.