Immense heat surge in my body?

The weirdest thing just happened and I don't know what it is was all about.

I was feeling really cold, so I put on a hoodie, then I put a warm sweater on over that, then I climbed under the covers to get really warm. My fingers were freezing and everything. And then, in just a few minutes, I could feel immense heat literally radiating from my chest. I could feel myself heating up and the heat surge up like I was in front of a fire or something, but it was only affecting my upper body. It kept building and building until my hands were even warm again- I thought I might burn up like when you get too hot- but when it reached a certain point it began to die down. Now it's stopped or dimmed to a low point, and I'm getting a bit cold again.

It was the weirdest thing, but does anyone have an explanation for why it happened?