So.... when you're miserable, and you hurt your body on purpose as a response, what is the distinction (is there one?) between doing it because you deserve to suffer vs doing it because pain on the outside is a distraction that's easier to cope with than pain on the inside?
So, if this were me, it wouldn't really be about hurting my body. I mean, seriously, I've hurt myself on purpose, and while the impulses have some areas of overlap, they're pretty distinct. (BTW, let me mention, not for the first time, some distress that these boards don't have the equivalent of an lj-cut tag.)
If that were me - I just can't speak for Chaz, and it's a very outside view - I would be throwing myself into that because I was turning my grief into rage because the grief would eat me alive or drown me if I didn't. Not that there wouldn't be plenty of rage there anyway. And I needed to take all that energy and push it in to something, to make something out of it. For me, there's an axiom that very focused physically demanding activities always help. I mean, always, if I can drag myself into it, no matter how much life sucks, that will help.* If it's something that kind of has a sense of poetic propriety in terms of why I'm so upset, all the better. If it's something I would normally approach cautiously, and which I can pull out all the stops and go all out, better yet. And if there's a chance I might get hurt or killed doing it... yeah, that sounds just perfect. I mean, it's not the goal, exactly. (Well, okay, there were times when the thought of throwing myself into it, and doing it as hard as I could until my body failed and hopefully in a way that killed me was pretty darned attractive, but that was quite a while ago, oh my wasted youth.)
Keep in mind, I was not a jock. I usually did something active, but I was bookish computer-y girl geek. (And yeah, I also wrote a lot of angsty poetry.) And I guess I should say that this all refers to earlier mes. Maybe present-me has grown up and gotten better coping skills. Hasn't really been put to the test recently... And I'm not sure it could be, in a really rigorous way. It's not always obvious which calamities are the things that totally destroy you, and which ones suck and you pick up your pack and go on. I mean, Chaz being torn up by Daphne's death isn't exactly a surprise... but in my own life things have not always been so clear cut.
Answering your original question (and while I'm going to be vague in my descriptions, I will be talking about self-harm, and this is where I'd put that lj-cut if I had such a thing), for me the two have taken different forms. I've done things that hurt because I was mad at or ashamed or myself. (Or for any other number of reasons. And that one gets squishy around the edges because in the kind of athletics I enjoy the line between something hurting and something feeling great is often very fine and squiggly. And this is where all of my friends who are into BDSM tend to make fun of me for not being into BDSM, but I am not making that call, either, out of ignorance.)
I'm making a distinction, I guess, between pain and lasting damage.** When I've harmed myself***, which hasn't been for a really long time^, it was because I was in the grip of what I thought was an unresolvable crisis. I would have chewed off my paw - heck, in comparison, that would have been pretty constructive. I would have been happy to think of something as useful as chewing off my paw. (I'm not saying my ability to evaluate my options was very good. Or that I wasn't an emo young thing.) It was more than using pain as a focus, it was the combination of a huge amount of emotional pressure and a sense of being completely trapped.
I don't pretend this description is particularly portable.
* This had been true for me for a long time, but I think it was clearest when I had heard that a good friend of a good friend and former girlfriend had been brutally raped, probably by the same guy who raped me when I was eighteen (this all was a dozen years later) and who for various reasons I hadn't prosecuted. Trying to confirm that it was the same person, my friend sent me a picture. (I'm still not certain, but like, 90% sure.) And then I had to leave for wushu practice. So, I drove across the lake in a gut churning mix of horrible feelings, trained my heart out... and then afterwards, all the neurochemical excess was just kind of gone. I mean, I was mad, I felt guilty, I was remembering some pretty unpleasant times in my own past, but I wasn't gnawed by it, but none of these things felt like they could really touch my balance.
(And if this explains something about how I took up a very acrobatic martial art as a way to recover from a spine injury, well. Yeah, the first six months were kind of horrible, and I can't exactly recommend it, except the results were pretty stunning.)
** There are few things I've felt as ashamed of as I did of having self inflicted scars. Which was pretty helpful in terms of not doing it again, actually, but extremely unpleasant at the time. I am really, really lucky that I heal scars as well and thoroughly as I do, or I would be a complete mess. (Most of them gained through exuberance and/or stupidity rather than anything so melodramatic, but still a great assortment. I think I have only two scars on my body that are more than ten years old - and even the dreadful bit on my face is almost impossible to see now.)
***And I'm excluding the things that made sense - minor surgery on myself when on the trail doesn't count. Anything involving athletics that wasn't deliberate self-harm doesn't count.
^ And only once as an adult, and a couple other times ever. Though for years, under certain kinds of stress, I'd find myself wanting to, and I hated that. Bah. Hasn't happened for a long time, though possibly becoming not-married was the biggest bit in resolving that. I think every instance as an adult involved the relationship that became my now former marriage.