What Are The Causes Of Nausea In The Chest And Light Headedness?

I have had this happen before and have had all sorts of tests done but they say my heart is as healty as can be...I wake up feeling nauseous (more in chest area) and have indigestion very bad, then after being up for a bit all of a sudden feel this weird wave come over me and my heart starts beating super fast...I feel strange and lightheaded and it lasts for a couple of minutes then goes away. But I feel very uncomfortable in my chest area afterwards. I have been to the ER twice for this and both times they have ruled out any heart issues and think it could be heartburn....I have been diagnosed with acid reflux but they say pretty mild. Well this happened again 2 nights ago but this time I also had back and left neck pain, felt like a pulled muscle on neck and collarbone, little stabbing pains in center mid back. I felt the back and neck pains the whole next day and felt tender and sore in the chest area, as well as headache behind my eyes. I was able to sleep last night and woke up this morning with two very swollen eyelids, but the chest feels much better and the neck & collarbone feel just more sore now.