Mr. Happy ~ I do not know about "fiddler's chin" but "fiddler's neck" is definitely a medical condition. When I first started playing the fiddle I was clamping down using too much pressure with my chin. Of course when something is new there is a tendency put in quite a few hours.

Anyway, one night I got this terrible pain in my neck to the point where I could hardly move my head. I thought there was a possibility of meningitis so I had my wife drive me to the hospital. The doctors ruled out the meningitis, which was a relief, and eventually decided I had fiddlers neck. This is not a joke. I ended up spending three days in the hospital on muscle relaxers and pain medication.

Whatever you do I would advise against using too much pressure with the chin and probably avoid long practice sessions when learning to play.

Cap't Bob