Finally got my pos OPK and im now 4 DPO!!?

morning ladies, i have finally got a BFP on my ovulation tests this weekend and today it would be 4 DPO and i have sore , is this due to my hormonal changes because of ovulation? i am quite irregular, i used to always be 28day cycle until a year ago went it just went haywire, and this month i actually ovulated on day 28 due i should be testin 2 weeks from now......that seems a long time i hope i can wait!! lol we BD'd the day before i got my pos OPK, what is the earlyest anybody got any slight changes??