What Causes Severe Cramping After A Hysterectomy?

I visited a new ObGyn yesterday to get a second opinion about bleeding (mini periods) more than 5 years after a hysterectomy. She used silver nitrate sticks -- warned there might be some cramping. She did ask how the cramping was before I left. By the time I got home I could barely stand up. I went to my bed and went fetal. Took 2 Tylenol and 2 Advil and felt no better. Incredible pain. I'm going to get an ultrasound and the return for another visit. It seems there may be more uterine tissue left behind than expected. Would that explain the severe pain? Is it unusual to have so severe cramping after a treatment? Is there anything to be done in event of future treatments?