Q. Our 14-year old son trains for his football team, part of which includes a long run. Recently he has had to stop running for a while because of a pain in his right shoulder. Could this be his heart? He doesn't get it playing football, and he is otherwise well.

A. A right shoulder pain is unlikely to be to do with his heart unless he is a 'mirror-image' twin with his heart on the right, rather than on the left, side. That’s a chance in many thousands. It may be a 'stitch' caused by cramp of the diaphragmatic muscle, pain from which appears in the shoulder. Or he could be running with his neck muscles tense. If it’s that, stretching and loosening his neck muscles before and during the run will help. He should see his doctor to make sure.