Starting physio again for the first time in over a year.used to go for knee probs but now going for fibro+cfs.what can i expect?mostly weakness+pains

Not much: Physical therapy has no long term value in the treatment of fibromyalgia. There are meds that can be effective.

Improvement: Teenager w. Fibromyalgia & CFS asks re exercise. Initially, land-based activity difficult. Start w. gentle walks & aqua therapy. Progress to gentle yoga & tai chi. Orthomolecular/nutritional regimen w. Vit D & protein to build muscle mass. Mindfulness therapies generate confidence & massage soothes muscles. Avoid naysayers & pity party Internet forums. Read books of those who improved this way.