Painful tendons under each breast, after enlargement sugery

My sisters both had Breast Enlargement Sugery on 9-26-06.
A week or two later they both have Painful Tight Tendons
under each Breast that run down in a straightish line across the stomache,
when they try and lift their arm over their head. I can see the
tendons streaching out the skin. Their Dr. said it was Tendons and they should Strech more. But it's not gettting better, any help in fixing this would be greatly appreciated. Thanks Chris