IF the doctor gives you this shot in the EXACT spot (is it cortisone..?), you can expect some decent pain relief for quite a while... many months. It is crucial that he/she administers the shot precisely, otherwise it'll be totally ineffective & you'll only be sore after; plus, you'll continue experiencing the same pain you're getting the shot to (hopefully) relieve. Also, if the shot is in a bony area, like a hip, or knee, etc., you can expect considerable pain for a day or 2 around the injection site. Good luck, hope they get it right! :)
The injections you will get are supposed to relieve the pain, and they do until they wear off. The injections themselves are a bit painful just like regular injections. Talk to your doctor about this for medical advice.
The injection is painful at first but then it gets numb and the pain relief can be from one day to three months. Everyone is different But you have to decide how bad you want pain relief. But make sure you are not allergic to the solutions in the injection or it could be deadly