7. Trauma
It is possible that you have fallen and caused a direct impact to the area, or that you are recovering from surgery. You may have suffered a direct trauma to the breast, you might have had surgery and are still recovering, or you might have torn or stretched tendons.
It can be confusing when you see signs of trauma, such as pain with inflammation, sensitivity, or bruising, but do not recall having experienced an impact. You may not remember a trauma that occurred while you were sleeping. It’s also possible that, at the time of the trauma, you did not think much about it. However, this minor trauma may have been more serious than what you initially thought.
Breasts can also be damaged in less obvious ways, such as by nursing (children can bite the nipples and cause injury), by rubbing against clothing (see next point), or sunburn.