You are being treated for heartburn or hiatal hernia, and you feel sudden chest or stomach pain, have difficulty swallowing, are vomiting, or are unable to have a bowel movement or pass gas; you may have a hernia that has become obstructed or strangulated, which are emergencies.
One strong possibility for your symptom is gall bladder stones and cholesterol deposits within the gall bladder which can cause sharp pain. Getting an ultrasound of the upper abdomen done in a walk in clinic or the ER will confirm the diagnosis.
The piriformis muscle turns out the foot by externally rotating a straight leg and slightly abducting (pull away) a leg when the knee bends. It does this by engaging and contracting in order to turn the leg open.