The magic answer
My daughter tried what seemed like every conceivable shoulder rest possible, and was never happy. We finally tried the Comford shoulder rest a year and a half ago, and it has proven to be the magic answer. She no longer complains about pain while she plays. Bonus: the Comford never falls off! I purchased both the tall and medium sizes for her to try, and she chose the medium -- however, her teacher tried the tall one, and liked it so well that we ended up giving it to her for Christmas. She has been using it ever since. We purchased the plastic models, and they are not too heavy.