Survivant depuis 2012
If that's your doctor's approach I would definitely seek another opinion. Rarely do breast surgeons take that approach. Whoever you see, insist that this be chased down until you get a definitive answer. It may require a surgical biopsy and a pathology read, but you absolutely DO NOT want this to sit.
I suggest you be as proactive as possible on this. As you probably know, "watching" a lump or suspicious area can cause major problems if it is malignant. Please know, though, that many lumps are NOT cancer. You just need to be sure.
Good luck to to you!