does this happen to anyone?

So my period started on October 26 and today it is probably gone cause I am just experiencing spotting. So my main concerned is can anyone explain it to me why am I having this pinching and pulling feeling on my lower righ abdomen ? This never happened before and it is really strong pinched. By the way , I had sex on the most fertile day of my cycle October 11 he didn't ejaculate inside me only from the outside of my vagina.