I read Sarno when I was suffering from "carpal tunnel" like symptoms that wouldn't heal. I didn't believe his claims, but his argument about the possibility of self-perpetuating psychosomatic pain made me put more effort into being happy, which was valuable.
In cases where you have inflamed or slipped disks pushing on the spinal nerve (e.g. sciatica), Sarno is completely inappropriate.
Of course, bulging or not-perfectly straight disks in an MRI or xray do not mean the pain should be solved by an operation - most symptom free people have some irregularities that will show up.
I discovered Sarno when I came down with untreatable "RSI". Eventually I got better using his approach. My story is similar to Rachels (google for others):
http://podolsky.everybody.org/rsi/
Sarno originally worked with people who had chronic untreatable back pain.
All that said, if you're not getting any exercise I would try that first. But if you have tried that and a bunch of other things and nothing works, look at Sarno.