I came across a great resource on very severe pain, its consequences, and its treatment and am posting the link in case it is helpful to anyone else:
Although the guide doesn't focus on chronic pain, but rather intractable pain which begins causing physiologic changes (such as autonomic dysfunction) and is severely debilitating, much of the information is useful for chronic pain patients as well, I think. I'm glad I'm not at this pain level all the time. Generally I'm lucky in that I can manage to prevent that level of pain by using my scooter, not doing too much, taking pain meds, etc. Sometimes I do have it for several days, sometimes longer. It's why I must remember to listen to my own body.
Last night I pointed out to my in-laws that the dog is always bouncy crazy around them, wanting to play, but never does that with me. They pointed out he moves carefully around me in order not to hurt me. I just thought he was avoiding me and had hurt feelings about it sometimes when he won't come close.