My 9 -year-old Son Is Having Pain In His Chest.

My 9 -year-old son is having pain in his chest. It goes with rapid heartbeat. But happens intermittently. The length of the episodes very from minutes to as many as five minutes. It happens at school sometimes. Most often at night before bed. He says it feels like someone is punching him. Sometimes if he gets too much exercise he has trouble breathing and feels like he's going to vomit. Not sure if this is related. He has no symptoms of as sometimes if he gets too much exercise he has trouble breathing and feels like he's going to vomit. Not sure if this is related. He has no symptoms of asthma such as coughing and wheezing.