Yeah when anything hurts you have to stop immediately. I would also question how did the injury start to happen in the first place. I personally find a lot of injuries occur when the fingers/thumb isolate their movements from the entire hand (a reason why practicing thirds wrongly can hurt), make sure when you play you keep the sense of the finger connected to the entire hand, this uses more gravity and weight of the hand to depress notes and produce accents rather than use excessive strikes of individual fingers.
yeah, my guess was right that it would be nerves. tendonitis doesnt have a sudden sharp pain. it's more creeping than sudden. but still be careful.
You're obviously a highly accomplished pianist. I enjoyed the recordings on your website. Do you possibly have a recording of you playing the Beethoven variations? I'd love to hear it.
OK sorry if this soundes too philosophical, But " if one stops doing the wrong thinngs, the wright thing should happen on its own"
I'm not sure exactly what you're getting at in this context. It seems to me that it is more than simply stopping an action that causes problems, but also actively replacing that action with another that is more anatomically and technically efficient.
Well exactly, you have just answerd your own question.