I've been experiencing a sharp burning pain located just below my sternum on both side of my chest. The pain then expands through my chest and and middle/upper back, neck and shoulder areas. When this happens, i can't slump over or curl up (which is my normal response to pain), because the pain just intensifys. It forces my to sit straight, when i do that, i get extremely dizzy and sick. After about 10-15 minutes the pain begins to fade away. what could be causing this? I prefer not to go to a GP unless i have to.