Why am I feeling an achy pain in my armpit? I am one month post op. Silicone 400cc unders, incision under breast.

Pain is very common in the first few months after surgery, even after the immediate postoperative surgical pain has resolved.  This is typically attributed to the healing of small nerves that have been stretched or divided during the procedure.  Pain, burning, numbness, tingling and other symptoms have all been described.  These symptoms can also be due to the fact that patients typically increase their activities as the weeks go by, and will often stress the surgical site or use muscles that have not been used in a while.  Be patient, it almost always resolves over time as long as the implant is soft and not malpositioned.  There are cases where the pain is due to a tight implant capsule, so if it persists or you are concerned, discuss it with your surgeon. 

Pain and electrically shock feelings that come and go post op are usually related to some small sensory nerve that was near enough to the surgery site to be irritated at surgery and maybe numb at first and now "waking up". Usually massage of the painful area any time it hurts will reeducate the nerve and the pain get better over time. Also show this to and discuss with your surgeon.

This could be nerve pain from a scarred nerve on the capsule (retrograde pain), or could be a leaking or ruptured silicone implant on that side.  If this persists, an MRI or an breast US would be indicated.

Dear acs,At 4 weeks post breast augmentation you are still very much in the healing period. When implants are placed - regardless of the position or incision placement - there is a good deal of stretch of the nerves that supply the breast. This where a lot of the soreness and numbness comes from. The nerve that exits the rib cage at the side of the breast especially is affected. This nerve branches and one part goes up to the armpit. As this nerve regenerates following injury, shooting, sharp pain can be felt in the armpit. It is similar to hitting your "funny bone" and feeling the sensation in your fingers. Be patient, these pains resolve in time.