If not heart related what causes pain on the right side of the chest for a few seconds then goes away just to come back later?

Right chest pain: It could be something called costochondritis, which is irritation of the joints where the ribs meet the breastbone. Could be a strained muscle between the ribs or one of the pectoral muscles. Could be inflammation of the lining of the lung, but usually that would be persistent. If really only for a few seconds at a time, it's most likely muscular.

Right sided: Can be reflux or muscle or anxiety or tension. If continues get it checked out.