My main muscles in the shoulder area as my MT tells me are my levator scapula, my infraspinatus, trapezius is a big one and my serratus....

I do a hang upside down type stretch like a yoga stretch. I bend at the waist and allow all to hang over my hips and as far down as I can get that day.....I then grasp both elbows with my hands and hand for a little while it takes the stress off the muscles. I also do a pendulum swing. Again bending over at the hips keep your back perpendicular to the floor hang on to a wall or something if you need balance and then let your arm hang straight down. Your arm starts by doing little circles then graduate up into larger ones....so pretend you are drawing circles on the floor and let your arm do the work.

I also do a yoga stretch called childs pose....
http://www.yogajournal.com/poses/475
good step by step instructions here.

http://www.yogajournal.com/poses/fin...rapeutic_focus
check that link out and see if you can find a pose or stretch that you like.

I also have a round bolster that I lay on top of and allow my arms to fall at my side. This opens up the shoulders and the chest muscles as the pec is sometimes an issue eith me and my shoulder posture. so perhaps try lying on a rolled up blanket like in a hotdog shape (the meat not the bun) and lay with it right on your spine and let yourself just hang over it. This feels great but do it for short periods and frequently this can be too rough if you don't do it slowly....I have had a sore chest from a long lie on the bolster....great stretch though....so with caution for all and go slowly

google shoulder stretch and see what you get and as you know....no overhead and always go easy on yourself...also I have found asking my MT is a great resource. She will tell me the exact exercise to do for the muscles in question!!!

Take care and hope some of this helps
love and hugs,
Victoria