I am also having similar symptoms. This isn't the case for me but yours could be an ulcer.20 mins after eating as the food leaves your stomach the ulcer is then exposed to the only thing left in your stomach, which is acid. When you eat again the ulcer is then protected by the food until the food passes out of the stomach again.
5. Dumping syndrome. Test: gastric emptying test.
Bloating my be due to
1. H. pylori infection of stomach. Dx: test for H. pylori
2. Lactose intolerance. Test: 2 days lactose-free diet, or breath test with lactose
3. Fructose malabsorption. Check here:
http://www.medhelp.org/posts/show/612997?post_id=post_3343636
4. Small intestinal bacterial overgrowth (SIBO) Dx: breath test with lactulose
fundiplication and yes to both
What kind of surgery have you had? Are you bloated, gassy?