Saul’s thread about both stealing students(reprehensible) and changing technique(leading to muscle damage) made me want to start a new thread on this subject.
Any technique, no matter how hairbrained it is, due to bad teaching or no teaching, will feel natural and comfortable to the player simply because he/she has been doing it over and over again. Any change to that(hairbrained) technique is going to feel uncomfortable and may even cause pain initially. But this will subside as the new muscle memory is established and the old one fades.
Years ago a very good professional harpist came to me and asked me to overhaul her technique. She had studied harp for a relatively short time and it had been over 20 years since her training had ended. Her technique had devolved into an awful mess. She herself told me that she felt that she was on the edge of calamity every time she performed.
Skipping many details here, I basically started her over teaching the French technique that I learned. I told her at the first lesson that for the coming 2 to 3 weeks this would all feel very uncomfortable and would hurt after a short time and for that reason she was absolutely forbidden to practice more than 5 minutes at any one sitting until it all started to feel comfortable.
When she came back the next week, I asked her what hurt. “Everything” she said. “My neck, my shoulders, my back, my arm…” We stuck to very slow, very easy things for another week or so and the discomfort that she initially had quickly went away. We were then able to really start building technique.
The reason for the discomfort was the ‘war’ going on between what she was used to doing, and the new technique she was learning. As the old muscle memory faded, so did the discomfort. By the way, I went through the exact same thing myself in the first months of studying with Pierre Jamet.
The point of this is, if you make significant changes to your technique, hand, arm, or finger position, it will initially feel uncomfortable. Do not under any circumstances practice with pain or discomfort. The second it starts, stop and rest. Come back a half hour later and practice some more, but stop the second there is any discomfort. In about 1 to 3 weeks, the changes will feel completely comfortable and natural.