Please look into this before getting cortizone injections. Google "platelet rich plasma therapy" and see what I am talking about. This is what athletes are doing now in order to heal cartlidge/tendons/muscle (virtually any connective tissue that has limited blood supply) quickly. Cortizone STOPS inflammation and makes you feel better, but inflammation IS neede in order for your body to heal more readily, so esentially cortizone is counterproductive. Enough research has been done to underscore that. Cortizone may make you feel better, but the tissue is exactly the same after treatment, its damaged, and we all know after a back injection that we are running around doing stuff we shouldn't. Pain is your body telling you to STOP or you will damage your body more, so we mute that signal instead of injecting something that has growth factors (platelet rich plasma) and CAN heal the disc.
As far as I understand, it IS covered by insurance and if not, it isn't THAT expensive.
It's worth looking into in my opinion.