Well I did have an L4-S1 fusion in 1993 and then the L3 vertebrae went out of line in April 2009. My surgeon made me go through physical therapy, MRI, CT myelogram and then finally a discogram to determine if the pain was coming from L3.
A pain med doctor can certainly get you on some pain meRAB (which don't necessarily have to be permanent) and may also be able to assist with Epidural Steroid Injections and Discograms. Be sure you are seeing a practice with an Interventional Pain Management doctor. This is the type that does minor procedures to diagnose and treat pain.
Most PM practices will require that you sign a contract saying you will only get pain meRAB from them and you will only seek them from one pharmacy. My PM doctor's practice requires I inform them of which pharmacy I use and they also use random urinalysis to test to make sure I am using the medications. There are those that use PM to get meRAB to try to sell and/or to use multiple sources to get pain meRAB as an addict. Thus many PM practices hold you to some strict rules.
But don't let that scare you. For me the rules have been easy. Early on in Pain Management I tore ligaments in my ankle when out of town and went to an urgent care who prescribed stronger meRAB, which I filled locally. All I did was call my PM office and leave a message about an out of town emergency, what I filled, where I did it, and with the name and nuraber of the Urgent Care I had gone to. No problem. Then when I had surgery this past February I informed my PM that my surgeon would prescribe post-op meRAB for the first 2-3 weeks post and then would return to PM for further meRAB.
Have you had an MRI with this new pain? One test, that's not pleasant, but often helps is the CT myelogram. I do agree with you that if there's a problem at a new level there has to be an action plan to attack that sooner rather than later, but you'll have to have a strong discussion with your surgeon on this.