What are they doing to treat your pain currently? What options do you have if you don't do the injections? Can they get you in with a CRPS specialist/pain management near you to help with that pain? I would tend to go for any non-invasive options first unless the injections are known to work and have a shot at alleviating most or all of your pain. I haven't had many in my back though so I'm not super knowledgeable in that area.