I have had heaviness in chest, can't breathe while laying flat, pain on the left side under my rib cage. They did chest x ray's and EKG, everything looked fine. They said I have chest wall inflammation from my RA, but now I can feel an air bubble or something under the skin on my left side that moves, kind of crackles when I touch it. Would could this be and what should I do?? I'm scared. I've been to the Dr and ER.