I've experienced something similar though it didn't last as long...
I was just diagnosed with anxiety a week ago, and yesterday I had an experience that my doctor thinks was a panic attack (if it was, it would be my first panic attack!) It started as a hot, burning sensation in my upper right arm. It then spread to my entire chest / upper torso, and at the same time I felt very faint and my heart was racing. However, it quickly went away after a few seconds. A few times later in the day when I started feeling anxious I could feel the burning start again, but if I could make myself calm down it went away.
My doctor is referring me to a cardiologist just to make sure it wasn't my heart, but I've had a few cardiac tests in the past that were fine and I have no risk factors, so he thinks it was a panic attack. I also just started taking Lexapro a few days ago and he said the Lexapro could have caused the faintness but not the burning sensation....