Re: EMF-sensitive here
"caused my hand to heat up and actually ache"
Cheap phone design. It was the battery heating up. Your hand wasn't cramping up because of the phone's electronics, it was cramping up because you were holding it in a position your hand wasn't built to be held in for any length of time. You only became aware of it due to the heating. Try holding an old-fashioned checkbook to your ear for half an hour or so while having a conversation. I'll bet you a plugged nickle your hand will start cramping up.