What Causes Pain In The Upper Back?

Hi. I overdosed 2days ago. My friend gave me CPR until the EMTs got there and then hit me with Naloxone, upon which I came to. Obviously I have no idea how things went down as I was man down myself. I m lucky to be alive, for sure! My question is, iv got a shooting pain in my upper back, between the shoulder blades. Going from sitting to standing I encounter some painful moments. I can t really bend down, I m just in alot of pain. I don t think it s a rib. I m worried maybe my spine took a beating during my friends lifesaving but untrained CPR. How worried should I be? And how long will I be sore?