Lump in Between Breast Implant and Chest Wall

The lump that you are feeling after breast feeding is most likely unrelated to the implants.  It is most likely benign breast changes associated with breast feeding.  However, it is important that it be evaluated.  The fact that an ultrasound did not show anything should not end your work up.  You should be evaluated by an experienced breast surgeon for further workup, which would likely involve an MRI at this point.

Breast-feeding can cause contracture or internal scarring due to contamination with bacteria from the baby's mouth. This scarring is circumferential and causes the pocket to shrink and the breast to be sore. What you are feeling may be nodular scar tissue or even some sort of growth behind the breast which is difficult for ultrasound to pick up. If there is any question I would recommend talking to your doctor about an MRI.