I found a lump next to my nipple, the size of a pecan one morning. It was there for four days and now it is gone. I can't find it anywhere. What happened? There has not been any injury there.
Hmmm... Well, the important thing is, it disappeared. Breast cancer lumps don't disappear on their own; they only grow larger. This might have been some clogged milk ducts; a small cyst that went away on its own; or something hormonal, connected to your period. Lumps can appear/disappear in synch with your period, often getting larger just before, then going away afterwards. Unless it reappears, I'd say don't worry about it. Hope this helps - PJH