My sons health

My son, who is 8, has recently started complaining about chest pains. These pains come at random times, whether he's been running around, or just sitting still. He also says that his heart beats really fast and then slows down again. When he has these pains, he has trouble breathing. I've also noticed that he's had a loss of appetite and is always so tired. I took him to see our family doctor and he wants to wait for a couple of weeks before we do any tests. Should I wait the couple of weeks and let my son suffer through the pain, or should I ask for a second opinion? What should I do? My dads side of the family has a history of heart problems. He just had a heart attack last year, and my brother had a mild heart attack at 30.