I would like to propose some general ethical reflections on the problem, or rather the experience of pain. What does “ethics” mean here? In extreme simplification we can understand it like this: reflection on human behavior to evaluate it in comparison to values (what is good and what is bad) and to orient it towards better forms.
In common language we use the terms pain and suffering with a certain indeterminacy. When e.g. a patient tries to explain to the doctor the symptoms that afflict him, he may say: "I feel a strong pain in my knee", or: "This arthrosis makes me suffer terribly". I don't want to go into overly refined conceptual distinctions here, more typical of philosophical thought or psychology. Pain and suffering are not the same. Both belong to the experience of suffering, but they are of different nature. They often go together, but can be distinguished. You can suffer without feeling pain: e.g. for an injustice suffered, for a betrayal, for one's own moral evil or that of others. Or you may experience a form of pain that does not cause suffering: e.g. an athlete in the effort of physical performance, a pain endured to achieve a greater good.