This would have been picked up on your mammogram, so I'm sure it's nothing to worry about. Probably breast recovering from surgery. Speak to your BCN in the morning who will have all the information.
Sending a gentle hug x
Hi. I don't know the answer but I had surgery on 7th and my boob is still bruised, sore and lumpy. Guess it just needs time to settle. I would ring your breast care nurse though just to put your mind at rest.