Had cortisone in AC joint. First one failed, hit bone and tingly shock wave through body. Second attempt successful but 28 hours later whole shoulder, up neck, down to elbow feels same pain as injection?

see your md. I assume you had ac joint injections for ac joint arthrosis or 'weight lifters' clavicle.If u are having the symptoms you are describing i would contact his office and see if you can't be seen fairly soon.Ac joint injections should not cause pain in neck, down arm etc.Any allergies? See your ors.
Ouch. Temporary improvement is likelly explained by the numbing medicine in the shot and confirms your problem is at ac joint. Steroids take 1-2 days to take effect. If you got better initially but had return of pain then the steroid attempt failed and you may need surgery.
Good news/Bad News. The good thing about an ac joint injection that works for a short time is that it confirms the diagnosis. As long as the injection was truly in the ac joint then we have confirmed that this is the source of your pain. However, if the pain comes back or new problems arise you should discuss with an orthopedic surgeon to see if surgery makes sense for you.