Burning dull ache in uterus? Possible Implantation

Hey yall I am 3 days before my period and I am having burning cramping dull ache in my uterus. I don't not have endo or fibroids and this is a new sensation for me. Did any of you experience this and then end up getting a BFP? Any information would be helping. I had surgery in Jan to check for all of that and I didn't have any issues. So idk what this could be?