I have recently begun a very rigorous core workout routine including Pilates and Yoga among other exercises. I did this to address new lower back issues and avoid surgery. I am experiencing sharp pains (almost feels like a rubber band snapping against the inside of my abdomen muscles) only while I am exercising my abs. I was banded back in 2005 and was told once a long time ago that sometimes I might feel pinching where the port tube goes through the abdomen wall. Has anyone else experienced this sensation while exercising?