okay, for a while now I have been having a tightness on the left side of my chest that sometimes moves down on to my left arm. I get short of breath and lightheaded sometimes. Sometimes my heart skips a beat or "flip flops". I have been to the doctor several times and the hospital. They said I'm fine. I go running every other day and I never have chest pain while I'm running or after, its always when I'm just doing nothing, like watching TV or talking to someone and I'll just start feeling like this. I've had blood work, EKGs, tilt table test, stress test and an ECHO test. All come back fine but I still have these symptoms. I'm always worried. I have no idea what it could be. Any suggestions would be great. Thank you.