16 yr old male. occasional chest pains, and random fast heart beat mostly at night. had recent ekg and physical. is this anxiety related or a concern?

Anxietry IS concern: I can't help thinking that a teen ought not have either cardiac issues or anxiety chronic or severe enough to cause such symptoms. But, reality is what it is. Ask your parent(s) to bring you to the doctor for a referral to a CBT therapist who can guide you to skills to avoid, reduce and manage anxiety. You'll have a much better chance for a good life and fun memories of what should be your youth.