Read up on sphincter of oddi dysfunction at:
http://hopkins-gi.org/pages/latin/templates/?pg=disease5&organ=3&disease=12&lang_id=1
I get an excruciating epigastric ==> RUQ pain, feeling exactly as you describe it (hunger pain, burning) about 2-3 hours after lunch and dinner. I had all the tests, including an MRCP but not an ERCP, and they have found nothing. I have failed 2 PPIs and an H2 blocker.
Remarkably, and thankfully, my pain goes away within a minute or so of drinking a large glass of water or eating. Somehow, that relaxes the SO.
The pain is so bad that if it didn't abate I would have to go to the ER immediately.
Good luck finding what's right for you.
I think the gastric empyting test is a good idea, your symptoms sound like those that come with gastroparesis, or delayed stomach emptying. In the meantime, try a few things; eat a low fat, low fiber diet, which you will find to be mostly carbs. Avoid whole grains, like oatmeal, etc, and nuts, popcorn, raw fruits and veggies, and foods high in fat. These all slow or impede the digestive process for those with stomach motility disorders. Also, eat smaller amounts more frequently, and try to elevate your head at night. Hope this helps. I have this disorder, and there are meds that can help, but it would be premature at this time to start taking anything. Post again with your result. Good luck.