I get that all the time because as a child I had a double hernia, and repaired, in my lower abdominal area, but please check it out with your Doctor, I find with my scar tissue, and after a soft bowel movement, or even a slight spasm, I get these waves of pulling around my floor, pelvic area, kinda residual pulling, like pings that trail down my butt cheeks, I know it's more annoying then the spasm like intense pain.
Please keep on checking in,every one is so helpful here, and eventually some one will nail your question in the butt..