Had thobbing back pain for years. Cardiologist called it angina and I did
Have blocked arteries. But despite being cleared I still had the
Back pain between the shoulder blades.Nothing ever helped nitro patches
Were negative. Funny thing is under a chemical stress test I have no pain whatsoever. Only on the treadmill.
Makes you wonder all these years, if the pain is from something else.
Had the spine checked the lungs too?

all I can tell you is my experience. I hard pain between my angel bones I call them that OK shoulder blades when I had gallbladder trouble. When you had your spine checked Did your doctor look at the x-rays or did he just read the report. There is a BIG difference. No one could find my problem until I went to a neurologist (nerve doc) I looked and found in 2 minutes. Good Luck! And don't give up. Check out Dr. Trester site on web. Look for the revolvng spine. It tells you allot of interesting stuff.

Another guess. Aneuryism or something leaking in the chest.

Happened to my uncle.