Pain's a good teacher. Most people when they get hurt feel that pain and know not to do it again. But if a healer wants to heal a broken bone it's their call. But there are varying degrees of injuries. I wouldn't heal a scratch as an example. A broken bone or deep laceration, that's a different story.
There's a thing called the Hippocratic Oath. Starts off with do no harm. That usually means helping those in need and that to me means healing people since I was given this power. It's our lives, our powers.