You don't need to go to a different doctor. You said you don't want to go to the doctor every month so realize a physical heart problem does not exist. You passed the EKG, so there is nothing wrong with your heart.
"when I'm busy or having fun i don't experience the pain." You can try a therapist to help you realize what you said is half of the answer and the other half is to stop worrying that you have chest pains. If you can stop worrying the pains will disappear - That might not be easy to do, but the therapist will try to help you through it.
You can read many people's stories on this forum about passing an EKG but having chest pains. They have a common issue - the chest pain is actually anxiety induced because the patient worries so much they over-analyse every twitch, ache, dizziness, etc. looking for clues to a "mystery disease".
Try a different doctor. By the way, did anything in your life change seven months ago?