I had this done two time (jawbone cut, tooth extracted in fragments, stitches thereafter) and while the healing process was annoying, it wasn't painful unless I tried eating solid foods with the wrong side of the mouth or something like that (which was a good indication of the fact that it was too early to do so, which helped healing faster, which is why - even discounting addiction issues - taking painkillers for avoidable pain is dangerous).
The "quite a few bone fragments migrated out" part sounds pretty bad, on the other hand; that's not really supposed to happen as far as I know.
I agree that the opiates probably weren't needed. I took the recommended dosage at first and just completely passed out for hours, so I have no idea how much pain I would have been in. After that, I cut the dose in half for the next day, until I got really sick of feeling foggy and just stopped entirely. (I found the whole "high" to be really annoying and not particularly pleasant, aside from the pain dulling properties. All I wanted to do was read and I couldn't do that.) I suspect ibuprofen would have been sufficient but I don't really know, either, since I took the surgeon's advice and took the opiates at first.
I do still have one wisdom tooth left. If I ever get that one out, I'll see how it goes without the opiates.
Bone fragments migrating out are apparently not that uncommon. Any bone piece that breaks off but doesn't get completely removed will eventually migrate out of the gums.
The "quite a few bone fragments migrated out" part sounds pretty bad, on the other hand; that's not really supposed to happen as far as I know.