Can sharp pain triggered by very deep breath be cause by gerd? i read it could be. happens during cardio-exercise. localized,sharp.1second

A bit atypical: For GERD to cause pain on inspiration. It would be more common that you have irritation/injury of one of the intercostal muscles(muscle between the ribs that help you take deep breaths) or one of the joints of the chest wall(as in costochondritis). It you are having this pain frequently and/or it's severe, see your doctor about this.