i have almost that same problem. i was diagnosed with gerd three months ago i was taking nexium for it and it seemed to have cleared it all up.... then all at once it came back but now i get the shakey, lightheaded, feeling, pain under my left rib cage, fullness in the middle of my chest, lump feeling in my throat, and sometimes that acidy taste when i burp in my throat and mouth, along with the heavy chest feeling and racing heart. i take zantac 150 now maybe itll work. idk...