Ann,
Have you already tried PT & body/posture work with advanced therapists, or a expert chiropractor that uses many PT modalities?

Do you get pinching feelings in your arm pits? swelling or puffiness?

The Edgelow program is a bodywork /therapy type of program - therapy , tools and training - I believe you can order the kit to learn at home - to stretch, relax, breathe properly and get the muscles loosened up and retrained.
http://www.edgelow.com/

Sharon Butler has explanations of what and how the pec minor can cause problems & good stretches too
My favorite book = Conquering Carpal Tunnel Syndrome and Other Repetitive Strain Injuries- by Sharon Butler has very good stretches for all RSI /TOS with info on posture causes and corrections. She has detailed stretching ideas to gently coax the damaged tissues to release-not to force them. her website: www.selfcare4rsi.com

http://www.selfcare4rsi.com/thoracic...e-anatomy.html