Both fibromyalgia and PTSD are disorders that western medicine (in my opinon) does a spectacularly poor job of addressing. The only thing western medicine offers for fibro is a myriad of pain relievers and antidepressants. Almost every single one of these medications actually interferes in subtle ways with sleep patterns. This is really sad, if you consider that sleep pattern interference is one of the biggest contributing factors in the development of fibro symptoms.
In the case of fibromyalgia, I think it is actually more helpful to look at the model of traditional chinese medicine (TCM). TCM views many illnesses as being blockages of chi or energy or blood in organ systems that are defined energetically and functionally rather than physiologically. (Okay, I know that sentence is a handful, but if you know TCM, you know what I mean!)
There are several patterns of blockages or deficiencies that are recognized for fibro, including spleen chi deficiency, liver chi stagnation, and several others.
A TCM practitioner may try to rectify the situation with accupuncture, accupressure, herbs or movement.
I think that one of the things that shou shu does, even for its beginning students, is to teach them to move them to move their body as a whole in a way that stimulates the movement of Chi. As we teach weapons to fire, be reinforced, and flow into the next weapon, you can easily imagine lines of energy being lit up and down the body as the muscles engage. And for me, it is easy to imagine that if there was blocked chi, learning Shou Shu would quickly unblock it. I suspect that it was this, more than anything that helped me.