It has now been 4 years since I resumed studying our beloved, but tyrannical, companion, after taking a very long break (more than 20 years); I am now 38.
Anyway, getting to the point, that shrewd harpy of a teacher thought it wise to propose an old study to me, which I thought had been archived long ago, but by changing the fingering—meaning the whole piece must be played using the 4/5 finger and all with a certain speed of execution, with position shifts, falls on the black keys, accents........ Anyway, it's a crazy pain, but is it normal that after 4 years of "serious" study I still find myself with 4/5 sore?
Well executed. If you observe closely, one must exploit, as she does, the back-and-forth motion of the hand and accommodate the fingers with a slight rotation of the forearm. I would not want to interfere with your instructions, but try to push the hand in on the 5th and pull on the 4th; naturally, the movement of "accommodating" must be minimal. The fingers, especially the 4th, will lift easily. You use the 4th and 3rd and lift the fingers well. You make good use of their fall, but with relaxation. It is a matter of coordination. If you feel pain, the movement is not correct.
I'm doing a bit like always, I close my eyes, play the piece and listen to my body, the brain focused on the movements; this often gives me useful suggestions regarding any errors due to incorrect movements.