Hi Jody, sounds similar to heart-opening pain.  Obviously, I couldn’t say for sure but the upper back/between the shoulder blade pain is a common pain to have during the biological changes that take place during the changeover to the new human-high heart/respiratory changes.

As we heal our wounds and move past the heartbreaks of our past, the heart chakra opens and we begin to experience more LOVE and joy as we release old emotional and physical toxins.  It’s also common with heart openings to experience occasional heartburn/indigestion, palpitations, irregular heartbeat, etc.

I notice these more whenever Venus (LOVE) is prominent in the skies, but keep in mind that chakras have both a front and a back aspect:

I myself have dealt with heart opening back and front pain acutely since 20010-ish and nothing seems to soothe it accept sometimes a salt bath and some heart chakra opening visualizations.

Speaking of which, Universal LOVE Breath has helped me on those late nights when the pain wakes me up out of a sound sleep…it was one of the reasons I wrote the guide.

I am sure others here are familiar with this discomfort that I am referring to, but only you know your body.

Hope this helps ♡