Anxious about symptoms of a heart attack

I have a sedentary lifestyle. Have high cholesterol for some time (160 LDL, 30 HDL, 300 TGL). No diabetes and Normal BP. I am overweight Since the last few weeks, I have been experiencing labored breathing here and there, sometimes accompanied by burping, I burp continuously. On most days I wake up with a feeling of nausea and heaviness around the throat area. Also i can feel my heart beating very hard (my HR goes from 72 to 90-95 at rest), this mostly happens when I am anxious or after a meal or if I have not taken a meal for a long time, I also feel quite weak at that time. I also sometimes feel a bit of uneasiness on my left arm and upper shoulder. All these symptoms don't happen every time and together. I went to a Gastro and they said it could be a gastric issue, mostly GERD/H.pylori and asked me to do an endoscopy. But I am a bit anxious if it is a heart related problem. Please help, do I need to be worried ?