No discernible lump, and am late fifties so unlikely to be hormonal. I've also excluded my bra causing it. Sometimes it's not noticeably painful, but is on palpation. I have fibromyalgia, so occasionally get a sore rib elsewhere, so wondered if that was it, but the painful part (partly in my armpit and also in the upper outer quadrant of my breast) doesn't seem to follow the path of a rib.
What would you do? It's been going on for about a month or so.