Why do i get the chills after a bowel movement?

Equilibration: Believe it or not, passing a bowel movement is an intricate, coordinated event that requires a specific sequence of nerves & muscles firing. One phase is the sympathetic phase, and the other is the parasympathetic phase. Brief (lasts < 5 seconds) chills immediately after a bm is part of the re-equilibration. Pain, or anything that lasts longer needs to be checked out by your doctor.