Why Do I Have Tightness In Lower Back And Groin After Suffering Missed Abortion?

I am 41 y/o, ht 5'2" wt 132lbs. Had D7C 9 days ago for missed abortion(9weeks & 3 days old) & feeling the tightness on my left groin then radiates to my lower back everytime I am walking over an hour. This is relieved by sitting down or laying down. Is this cramping. I don't have much bleeding anymore. Is this a normal process for healing.