@bigredak
I recently strained my back and was having palpitations. The sudden pain and strong palpitations when looking down (doing laptop work) it was quite strong so i first had my heart checked and it was fine, so I was sent home. Its been happening again several times per day, I suspect it is spine related. I was frustratingly looking online for a similar case, finally found your original post and it was like I had written it myself - I’m also 6”6, athletic, and I’m no stranger to sore back.
So, I will be making an appointment to get that checked and follow your process because it sounds like things have improved for you