I had major chest pain that require calling the paramedics. While driving I started to feel like I was going to vomit, dizzy, sweating lots, light headed, chest pain, having problems breathing. I couldn't call 911 myself, because I was too disoriented. When the ambulance arrived they gave me 5 shots of nitrous on the way to the hospital. My vitals we very high and I was sweating so much the heart monitors would not stick. Since then I have had a stress test, blood work etc. Bottom line, they cannot find anything wrong with me. They said I had every symptom possible indicating a heart attack, but nothing has showed up in any test. I am 46 years old, 150lbs, do not smoke, and very seldom eat fatty foods. All blood work was normal. After a few months I wrote it off as an isolated incident until this week. Twice the same symptoms have come back, but not quite bad enough to go to the hospital. Dizzy, feeling like vomiting, major pain in the center of my chest, a lump in my throat, loss of appetite, quite gassy and after I start to come around I am exhausted. It has only happened during the day, and I don't believe I was stressed enough for this to be the cause. Please advise.