Flute is notorious for causing hand pain, because you have to hold your hand off to the side and reach for the keys. I have a flute with openholes and a non-offet G key, and I pretty quickly had to put a plug in the open key for the left ring finger and press that key only with my fingertip. Jeanne Baxtresser, the former principal flutist of the New York Philharmonic, had extensions made for both that key and the G# key.