Ash, I ALWAYS felt sore bbs every cycle before AF, but when I got my first BFP, i they did not get sore at all so for me it turned out to be a good sign. That was 3 years ago (I've had 2 babies since then) and I just started getting sore bbs again before AF a few months ago. This cycle I noticed it started at 1 dpo. I don't think its a sign of anything just yet because I think its too early for sxs.