What Causes Tingling Sensation And Numbness During Bowel Movement?

I recently had a urethroplasty and it told me not to strain when going poop but it was hard not to because I was constipated. When I finished I had this weird feeling like a tingling or semi numbness. I was wondering if it was painful to tear the stitches of the urethra that was reattached or if it was what I had felt.