There's also minor dislocations called "subluxations" (can happen often if you've had a more severe dislocation previously) which is not typically a major thing, some annoying pain for a couple days. Maybe that is what he had.
But I'm not a medical professional, just my personal experiences.
True. If you actually dislocate your shoulder, after it heals, it is inherently looser, as the ligaments and joint capsule have been stretched out, are non-contractile, and can't 'tighten' back up, without help (surgery). So later, the person can suffer recurrent joint subluxations, and is prone to these.
If a person is a high level athlete, surgery is often the best option. I think this is why Fish had to have surgery. I think he dislocated his shoulder and wanted to get it 'fixed'.
I'm not sure, but I don't think Hason has ever had a dislocated shoulder, not sure though.