I was lying on my back in bed last night, meditating, and I noticed the surface of my chest felt warm. The lamp I was reading by has a shade on it and it wasn't shining directly on my chest. The thermostat in the room said the temperature was 78. The warmth seemed to be generated by my skin, and I was wearing a shirt when l was outside earlier in the day. I don't have any sunburn. Is this unusual, or is it something I just noticed because I was lying quietly and trying to be aware of what I was feeling?