Question: How Do I Get Rid of a Side Stitch? Answer: A side stitch is a sharp, intense pain under the lower edge of the ribcage caused by a muscle spasm of the diaphragm. They're common in novice runners who tend to breathe more quickly and shallow. Cause of Side Stitches What exactly causes them? When we inhale, our lungs fill with air, which press the diaphragm downward. When we exhale, the d…