I have chronic "episodes". They come and go none for days even weeks then several in a day for days in a row. Started 8 years ago after last child but are getting more intense and frequent. An episode consists of: a warming feeling starting in the chest, moves up the throat to the mouth. Mouth gets a metallic taste and vision begins to blurr. I get a feeling of either needing to vomit or have a bowel movement. Episodes lasts anywhere from 10-60 seconds. Seen multiple doctors in multiple states. Have had an EKG, head CT, EchoCardio, Stress test, all blood tests including allergy. Tracked my food and blood sugar for 30 days and didn't uncover anything. All tests were a pass. Don't drink too much caffine (1-2 diet cokes per day) but mostly water. Exercise regularly for the past 6 months and changed my eating habits over the past 3 months. Much healthier habits but symptoms haven't changed.