Do you happen to wear bras with underwires? I had something similar and it turned out to be the underwires were cutting into the area and causing the sore spot.
Since this could have started around ovulation, it may be hormonal, but it doesn't hurt getting it checked, especially if it doesn't clear up with your period, and you have no relief from wearing a different bra, etc. (Some breast pain is caused by poorly fitting bras.)
https://www.sbi-online.org/endtheconfusion/Blog/TabId/546/ArtMID/1586/ArticleID/564/My-breasts-hurt-Should-I-be-worried.aspx
https://www.mayoclinic.org/diseases-conditions/breast-pain/symptoms-causes/syc-20350423
Let us know what happens, and hope you feel better soon!
Forgot to mention I am 35