Good news is you have been evaluated and your heart appears to be healthy. This very well could mean your issue is more lifestyle related. Stomach issues like acid reflux will cause the heart to act up. Eating a meal high in carbs will do it as well as eating too big a meal. What is your weight and how active are you? Your symptoms could mean that your heart simply needs to be a bit more conditioned. Adding a bit of cardio to your routine may help the heart feel less strained. Also make sure your drink plenty of water. When structural issues with the heart have been ruled it, it really falls in our lap to find and eliminate the things that make our heart behave poorly. I wish you the best of luck resolving yours. Keep us posted on how you are and don't hesitate to go back to the doctor if you still have concerns or your symptoms worsen. Take care.
also just moving makes my heart beat hard like getting up or tying to do something like clean the house