I am a cardiologist and I read your details with diligence.
My simple opinion is same as your cardiologist no this pain is not due to heart. Obviously, next question you will have for your doctor will be what it is because of? Few more details are needed. How much is your weight? What is relation of pain to food intake (as spilling of food contents from stomach to food pipe that is re flux esophagitis
can be other cause) and cervical spondylosis
can be yet another cause. These are suggestions which I urge you to discuss with your doctor.
Dr Anil Grover