Just wondering what could be causing the pain in my sternum? I am 1 week post op breast aug, under the muscle.

It is common to have pain in the sternal area after breast augment, especially after a sub muscular augment. The medial pectoral fibers attach there and are on stretch. Sometimes you can get other "spasms" and "zingers" due the stretch of muscle and nerves. It all goes away with time. No worries. Good Luck!

This is very normal especially after placing the implants sub muscularly. I would expect for this pain to get better in the next week or so.

Most surgeons will disrupt some of the attachments of the pectoralis major muscle to the lower portion of the sternum when placing implants under the muscle. This can remain sore for a variable amount of time after surgery, but almost always resolves within the first month. After one week, it is fine to treat this discomfort with over the counter anti-inflammatory medication such as ibuprofen.