Chest pain on and off for months

Hi im a 17 year old male, relatively healthy and active and I've been experiencing chest pain, the chest pain im experiencing is on my left chest and it occurs for a second but it is becoming more frequent. To describe the pain, it would be like sharp tight pain if that makes sense. Sometimes i get this feeling in my chest that if i put my hand where my heart is i can feel my heart fluttering(i dont know how else to describe it), and when this happens i dont believe my heart is skipping a beat but it does beat rapidly. Ive had multiple ekg's that came back normal, chest x ray and a full blood count that came back normal. I dont think this is just anxiety as i do have a heart murmur but doctors believe this is unrelated as that is only a minor murmur. For the chest pain i experienced a month ago the doctor prescribed naproxen which relieved the chest pain. Recently ive ran out, and now im getting these flutter like feelings of my heart which is different to the chest pain i experienced one month ago. Does anyone else experience this? How do you stop it?

Im also writing this in the middle of the night where the pain started around 5-10 minute after i woke up but i was expecting it, im currently scared to go back to sleep

EDIT: The chest pain i would describe as dull i think

Do you have any breathing problems?

No breathing is normal, everything else is normal