I believe gastritis and GERD can cause about every symptom known to man. I've read most of them on this forum.
I have never had heart palpitations, but some people on here have. If I were you, I'd have my heart checked out. I'm sure it will be be totally normal and then you NEED TO FORGET about IT. Stress and anxiety make heart palpitations much worse. You become hyper aware of every little thing. If you believe you suffer from anxiety and worry a lot about your health, you might check out the anxiety forum on this board. There's a lot of good info there. I've had good reason to worry about my health in the last year or so, but I found the worry and anxiety was really consuming my life. I needed to get a handle on it and put it in perspective.
Is your doctor recommending any treatment for your ulcers and your gastritis? In my reading, I believe the vast majority of hiatal hernias are not a problem, but I know esophagus spasms are definitely painful...they were agony for me. If you aren't seeing a gastro doctor, I'd get to one and get on a PPI and also try some at home treatment for GERD. Make all the lifestyle changes you can. See what helps. We have a thread with good info in this forum. It should be near the top.
Hope you feel better soon:)