One caution I do remember, Ebbie, from exercises I did for shoulder and arm problems, was to be sure, if using small free weights, to always keep my hands turned in with the palms facing my body, instead of the usual way of picking up the weight and lifting it so that the palms face outward. I can't remember exactly why but doing the latter was a big no-no if there were any shoulder problems.

Lee Holden has very good, very gentle qi gong and/or tai chi DVDs for specific problems and general overall stretching and strengthening. You can see video excerpts and learn more at Exercise to Heal and at Lee Holden dot com. I highly recommend them, esp. as there is a version to fit almost anyone's needs, including doing it whilst sitting.