Broken rib for more than a year

i had a fall on my sternum almost two years back. i fractured my sternum and dislocated a rib at the back. doctor said it was partly dislocated. he told me to do the some breathing exercise and some physical exercise. i was out of pain for a long time until recently when playing football the pain started again. now it hurts every time i run. i don't get any pain while walking, talking or sleeping. only while running. please help