I've had problems with acid reflux in the past and sometimes I feel great pressure like you described, I feel I need to burp or throw up to relieve it. Sometimes it works for me to stretch my arms as far up in the air as possible. (sometimes...not always)

A few years ago I had sudden pain in my chest, felt like my head was gonna explode, and just plain felt weird. My mom took one look at me and freaked! She said I was pale as a ghost and thought I was having a heart attack so she took me to the ER. When I got there everything pointed to a heart attack and they gave me nitro. After several hours in the ER they transferred me to a different hospital to the heart unit.

After the tried to kill me on the treadmill and countless tests the dr. finally figured it out. My heart is fine.......I was having spasms of the esophagus creating heart attack like symptoms.

This was before being dxd with MS btw.......

I hope you get to feeling better and can figure out what's going on....I know it's awful to get like that.