On Sunday I was rushed to the hospital with a tightening of the left side. My face, neck, chest and arm, with a evere shortness of breath. I was released hours later with no explanation. Blood work was done and they said all was well. Since I've been experiencing more pain and discomfort. When I lay down my heart beats extremely hard, then I feel the tightness and discomfort on my left side of face, chest, arm with the same shortness of breath with some nausea. When I lay flat I can see my heart beat in my stomach, and when I close my eyes I can't sleep because of my eyes pulsating and twitching to my heartbeat. Last night I was up all night, but I got up with no discomfort, but when I got to work and began to move around the tightness and the excelled heartbeat and shortness of breath is back. What could be wrong? There's a lot of heartburn as well