Referred pain can be hard to pin down. The vagus nerve came to my mind as well, since it's involved with so many functions and parts of the body. When I would get very bad heartburn, I would get pain in my jaw and ear, but not the back of my head.
Still, everyone is different, and if you reported it to your doc and he/she isn't concerned, I'd chalk it up to one of those quirks unique to you alone! I'd bet someone else has experienced it, but I haven't heard it yet.
Nissen Fundoplication 2/09
"Whatever you fight, you strengthen, and what you resist, persists.”
“Worry pretends to be necessary but serves no useful purpose”
“Accept - then act. Whatever the present moment contains, accept it as if you had chosen it. Always work with it, not against it.”