Hello~you may very well have a hiatal hernia and this is causing GERD, or acid reflux, both will cause the exact symptoms you are experiencing. Try drinking small amounts of aloe vera juice before each meal and at bedtime, this might help. I would also see your GP, you might need to have an upper GI performed to determine what is going on.
I've had issues similar to this although the pain was in my esophogus when swallowing. In my case this was due to copper deficiency (due to taking zinc tablets - too much zinc lowers copper) affecting my nerves. I also had excessive saliva and difficulty swallowing due to vitamin B12 deficiency (another deficiency that affects the nerves). Sounds like you also have some neurological issue going on although I can't say what is causing it.