Ali,
OUCH
. I was surprised by the number of nurses complaining of back problems but after talking to a few of them, I no longer wonder. This is a serious issue and seemingly ignored by the medical community at large. I'm surprised w/c hasn't interfered. In CA, what about OSHA?
A discogram discovers which discs are pain generators and it sounds like you have 4 bad levels. Speaking only from personal experience with absolutely no expertise, you may be heading for surgery where your choice of doctors is beyond important.
Good luck and keep us posted, Dale