Hello Jo...
Sorry to hear about your painful shoulders. Fortunately for me, the RA only attacks my Rotator Cuffs occasionally but I try to relieve the pain and stiffness by doing a little exercise my Physiotherapist recommended which involves a tin of baked beans!
Yes, I thought she'd taken leave of her senses until she explained that by holding a 'weight' in your cupped hand and gently swinging your arm backward and forward you could encourage release of the shoulder joint without hardly any pain. This movement should never be forced and should only continue for a few seconds - and then change hands. If this feels comfortable then you could try swinging the 'weight' in front of your body from left to right which encourages the shoulder to release away from the side of the body - and then change hands.
A tin of baked beans works for me somethimes, when I can't move my arms in the morning, but I have to ask my husband to reach up into the cupboard to get them down for me!
I hope you enjoyed that - a bit of fun for a painful problem but it might help.
Ellie