I am curious to know more about the Somatic Experiencing.... Is it also focused on trauma release?
Somatic Experiencing was developed by Peter Levine. He wrote a book about it called "Waking the Tiger." I have not studied it extensively, but know that it, as with many other somatic trauma therapies, works a lot with resourcing (working with a person to be easily able to access positive states). Once a person is sufficiently resourced, they can explore the traumatic material. Therapy may use a process of pendulation, in which the person explores the traumatic material, then, if it becomes too overwhelming, is directed back to a resourced state, back to the traumatic memory for a bit, and back and forth again. The point is that most of us dissociate from traumatic material if we get too much of it at once, so you have to work with it in little pieces, a process known as titration.
In my experience, I was directed to look around the room at things that I enjoyed looking at, then feel the sense of that enjoyment in my body, looping back and forth. We can really do this with all of the senses, including the internal felt sense "Even in the midst of pain, see if you can find a place in your body that feels neutral, or even pleasant", but the visual sense is a good one. One of the scary things about being in a crash/flare up is the sense of feeling out of control, and by learning/practicing these resourcing techniques, we learn that we have more control over our mind states than we thought.
That's the resourcing part. The trauma release part supposes that we have some basic reactions to a traumatic situation (Fight, Flight, Freeze, and the lesser-know Fawn, in which we appeal to the mercy of our attacker, if an attacker exists). According to Levine's theory, when faced with a traumatic situation, we have an initial Fight or Flight reaction, but if neither of those reactions is realistic, we resort to a numbing Freeze, which is how trauma is stored in the body. A Fight or Flight reaction wanted to happen, but was Frozen. SE, and other traumatic therapies work somatically with the impulse that wanted to happen, under the belief that if the original impulse is completed, the trauma can be resolved. Other trauma theories, such as Sensorimotor Psychotherapy, operate under similar assumptions.
A while back, I posted the assumption that chronic illness, as it messes with our nervous systems as a trauma would, can be thought of as a trauma, and, if so, the mental suffering caused by it may be able to be partially ameliorated through somatic trauma therapies. I didn't find much on the topic out there, though. I think having a bad flare-up is akin to being physically tortured, in which one is subjected to physical pain, is unable to escape or make it stop, and doesn't know when it will end. In this case, a dissociative response would be quite appropriate. In the case of CFS/other chronic illness, I think the resourcing aspects of SE and other such therapies can be quite helpful. I'm not sure if the trauma release work would be all that helpful, though, unless there were specific associated traumatic memories, as the traumatic stressor (the illness) is ongoing. What might be helpful is an increased ability to tolerate the process of looking at painful sensation "as it is," without judgment or dissociating - the mindfulness mentioned by others above.