Always use pain as your guide. Whenever you have pain in your body, it means something is off and needs resetting.
Mid-spine (middle of the back) is where all the upper body's weight gets concentrated. Injuries in these areas are very common.
But step 1 would be an Xray. We need this to see if there are any mal-alignments.
Next Steps
Visit a local orthopedic, get an xray and please consult a good physiotherapist (thru' reference only) for long term help. Good luck!