I hope this discussion is still going on. I have these internal shaking and cramps in my sternum. It happens right when I lay down, but occasionally it'll start if I'm not laying down either. My cardio thinks it's my severe gastritis that's causing it but I take my meds religiously and I've done all kinds of heart tests to rule out a problem with the heart. I haven't had any luck finding out the culprit. I am happy I have stumble upon this discussion. Any new findings??