I've had an issue lately when I go to sleep I feel this shaking or quaking feeling in my chest. Has anyone else had this issue in relation to using a CPAP machine? Is the pressure set too high? I've lost about 50 pounds since I started using my machine. Is it possible this feeling has nothing to do with the CPAP? It's been getting worse lately (last night, I was only able to sleep about four hours). Any help is greatly appreciated.