I have problems as well with my rotator cuffs and it is definitely painful. And forget about range of motion (ROM).

But, you can lessen the pain and increase your ROM.
There are tons of exercises that you can do, and trust me, it may seem like you are barely moving but keep at it every day. Very slowly, it gets better.
I work with a trainer twice a week and he knows all too well about my limitations, so we are always including a few exercises for my rotator cuffs.
I also do some every day on my own, and it really helps me get through the day.
Here are some links that explain the exercises, and you can find some other sites too.
http://www.orthoassociates.com/shoulder1.htm

http://www.shoulder-pain-management.com/shoulderrotatorcuffexercises.html

http://www.thestretchinghandbook.com/archives/rotator-cuff-injury.php
http://www.itendonitis.com/5-exercises-for-rotator-cuff-tendonitis.html
http://preventdisease.com/fitness/sportinjuries/articles/rotatorcuff.html

There are alot more, so just do a search using
rotator cuff tendonitis exercises

Remember:
It hurts horribly, but it helps.

My wife has got a rotator cuff injury, she did it 3 months ago, after a week got referred to a surgeon, she has had physio every week and exercises to do every day. She has got some range of motion back, but is still in constant pain, they did a scan but nothing has been torn that they could see.
She is now down to have surgery in February to try and get more movement in it. They said it reacted badly to the injury and has frozen up.

My dr says i have this too and for me it burns in to my arm pit and on the front side of my shoulder to the top of my bra strap today is better but dam i cant sew any more nor do i move it much, i had an xray today and most likely cant get intot he surgeon until March which isnt so bad and for get taking much for pain relief i take tylenol extra strength and that is all i take but my son keeps telling me mom go get some weed and try that it wont hurt any more and believe me i am seriously thingking about this