How many DPO can you begin experiencing pregnancy symptoms ?

I ask because I just went through my cycle day 21 blood testing this past week and it was over 21! I’m currently on CD 24, 8 DPO and my boobs are over the top sore. Like they are so sore to the point where even moving around, my nipples hurt 10x the amount it normally does before my period. Has this ever happened to any of you guys?