I don't have personal experience with your health problem but you may find the following two articles helpful.
http://www.yogajournal.com/practice/1220_1.cfm
http://www.immunesupport.com/...narticle.cfm?ID=6004
Yoga International Magazine had an article about Yoga for Fibromyalgia in their last issue (april/may 2005).
Have you tried to change your diet? Eating fatty fish, flax seeds and walnut oil provide omega 3-fatty acids which have an antiinflammatory effect. You can also increase your intake of antioxidants trough eating a lot of fruits and vegetables. This may also be benefitial.
All the best for you!