A spasm of the pylorus will also cause this type of symptom.

It can be tested for with the upper GI. (also it can be relieved with an antispasmotic drug like Levsin.) I often get this because my GI tract is twisted... a rare congenital thing I was born with.

Also an upper GI "may" show a hiatal hernia. Mine showed up dramatically and I even had to lie on my right side and drink MORE Barium! However, my doctor said only about 10% of hiatal hernias show up.

When the stomach and esophagus move up thru the hernia, there is a pressure and feeling of "doom". I have learned to live with it. One thing is to NOT bend over after eating and not eat large amounts of food at a time.

For bloating, you can take Gas-X (or any simethacone product) and it will help you to burp and reduce discomforts. Gas is one thing that will make GERD/heartburn much worse.

I use a Maalox product with both calcium and simethacone in it to help move things along better, sometimes. I avoid carbonated drinks, and gassy foods too. But you can do the simethacone alone if you want.

I'd get the upper GI... it will probably be useful. The upper GI can be ordered with a small intestine request. They will have you sit around after the upper GI and see how long the barium takes to move thru the upper intestine. For me it was 20 minutes instead of 3 hrs (normal)...because of the maltodextrin in the suspending agent for the barium. I am intolerant of that, so my barium moved thru in a BLAST! They barely had time to take the X-rays to show it even. If your stomach holds the barium too long, that will show up as well.