Sore Boobs- in one spot!

Jessica
Hi guys!
We're trying to conceive at the moment. I'm in the two week wait.
I regularly get very achey boobs during the luteal phase. However, today I have a spot about the size of my palm that is acutely painful- when I move it feels like its being knived! 
It's so so sore!!
Is this normal? Is it a pregnancy sign? Is it something I should be concerned about?
Thanks, gals x