How To Cure Severe Pain On Right Side Of Rib Cage During Workout?

Hi, I am a 19 year old, active female. I had trained my body to run on the treadmill for about 5 miles at 7 miles her hour with ease. I took a break off when the holidays came around, knowing I would have to train myself to get back into shape. For the past 5 days I have tried running and within 2 minutes I get a severe pain on my right side just below my rib cage. I have tried drinking more water, stretching more, and I never eat a large meal before running. I have never had this problem before but it is really putting a damper on my workouts. what can I do?