What could cause muscle spasms between the ribs and a feeling like a rubber band is around my chest? I get strong spasms in between my ribs, and around to the back and they are very strong. I am not exercising when this happens. Also, my abdomen (diaphram area) tightens and I feel like a rubber bands is squeezing my insides. I have asked two of my doctors and one suggested I warm up before exercising. What else could it be?