If the pain is between your shoulder blades it probably isn't your spine...
I have had bad backs on and off all my life. I have a dislocated tailbone that can't be fixed ( fell on icy concrete step) and my SI joint becomes inflamed if I walk too long or sit on soft surfaces.
The shoulder blade pain is probably muscular. I found a lot of my pain went away when I followed the physio's advice and strengthened my back muscles. It is worth a visit. Ask specifically for exercises that will strengthen your upper back.