@Decadian. Yes some people never heal. But some people never got the right help. Some people like to play victim. Some people have it really tough and complicated MI's - that doctors struggle to treat.
I think some wounds heal - but they heal with scars. And some scars are always sore to touch. And scars never heal back and look like our old skin - our original skin. Thry are different, because an injury occurred.
Some scars we can live with. While other scars will always be painful. We just hope that the pain is not as intense as the original injury was.
Not all MI or physical pain can be 'cured'. Most of the time we need to learn how to create a life anf live that life as well as we can. And that in itself - is wonderful.
Have you ever considered a pain pump/ medication pump implanted under your skin? A dr I worked for - offered this for some patients.