My son has been struggling to breathe when exercising. he gets very panicky and he says his heart is racing. suspect exercise induced asthma. should i go to a gp for tests or direct to pulmonologist?

Might be or not: This can also be a condition called vocal cord dysfunction where the cords close erratically & interferes with breathing. It can look & act the same. Start with his doc. You did not list his age, which is important in sorting this out, but the doc who knows him is the place I would start. He may need to see an ENT and speech therapist & not a lung doc.