A lot has to do with the nature of the pain. Generally it is of a pleuritic nature. Sometimes it is impossible to inhale past a certain point without feeling sharp pain. Warm baths twice a day and gentle massage often help, with a few weeks of rest. Very, very rarely, such pain can be a precurser to a condition known as a spontaneous pneumothorax. It is extremely unlikely this will happen, however if the pain becomes extreme and is accompanies by air hunger, do not hesitate to call 911 for a proper evaluation by a physician. Often these conditions (the pain) are self-limiting.
Hi
Welcome to the forum!
Rib pain in a child who did rigorous exercise just indicates a poor oxygen supply. This can be due to asthma. It can also be due to anemia. The child would also need to be investigated for low blood cell count.
Hope this helps. Please let me know if there is any thing else and do keep me posted. Take care!