One of the treatments for back pain is called a trigger point injection.  A trigger point injection is where anesthetic is injected into muscles to relieve back pain.  There can be more than one injection administered at a time.    The point of the anesthetic is to deaden the area surrounding the point where the pain seems to generate.

Another type of injection is the facet injection.  The facet joint is where two vertebrae meet and the joint enables you to use your spine for motion.  The facet injection usually is a steroid, but it can be an anesthetic too like the trigger point injection.  The difference is the facet injection is done on an outpatient basis using fluoroscopy.  Fluoroscopy enables the physician to watch where the injection is reaching in the joint.  You can only get temporary relief from pain of course.  Both injections are just treatments and not cures.