Can any of you share your stories on SCS and/or Nerve block injections?

Which seems to help better?
I understand everyone reacts different with treatments, I really want to know what to expect with either one of these.

Do the nerve block injections last or are they to just give an idea about the nerves involved? I can not understand why they are thinking of doing these injections, because I've heard they don't last.

Are the injections steroids?

Sorry for all the questions....Thanks for your help.

I'm really confused at what the doctors are saying, some say SCS some say injections....