Hi Lisa-Jane! I'm new too, just so you know.
I get the same feeling in my chest, and experience the same breathlessness. Sometimes it feels like my heart is skipping beats, almost like it's fluttering. And then there are times when I'll get a big burst of anxiety (not quite a panic attack, just an extra shot of adrenaline for no reason), and afterwards my heart beats very heavily and quickly for a minute or so. And my ears ring a little also. I haven't actually experienced the chest pain you describe that lasts for days, although I may not have as severe of anxiety as you do. If you've gotten your heart checked out and things are okay, it's got to be caused by the anxiety. Over time, the stress on your heart can lead to heart problems (you're making your heart work a lot harder than normal), so it's important to do something about the anxiety. Are you taking any medication?