Dear TearyThunder: It is likely that the pain she is experiencing could be from the severed nerves but
pressurePressure ulcer from fluid can also be a reason for discomfort. Fluid can form as a result of trauma to the area and disruption of the normal tissue drainage system. Did your sister have a drain after the mastectomy? Sometimes a person may need to have a drain placed until the fluid collection subsides. She should discuss this with her physician.