In a small randomised trial of 64 women with fibromyalgia, those randomised to ten minutes of moderate-intensity exercise (50 to 70% of age-predicted heart rate) three times per week plus one 45 minute stretching session had improvements in many outcomes after 12 weeks compared with those who got exercise alone.1
The findings included increased sleep quality and a decreased impact of fibromyalgia on the quality of life and reduced pain scores.
The stretching exercises included three repetitions of tens seconds for trunk muscles and two repetitions of ten seconds for extremity muscles. There were 19 types of stretching activities which you can see in the reference.