Seeking Statistics of Disc Herniation

I am a middle-aged male in good health. In 2005, and in 2007, I have substantial acute lower back pain, associated with severe physical exercise on my part. At least I take comfort in knowing that much...the proximate causes.

Some 12 years ago, I strained something in my lower back, stupidly attempting to lift a heavy desk from a squat position. I could feel a hot rush on both sides of my lumbar spine, at the moment of lifting, on that occasion. I knew I was impaired at that moment, and made it home that evening after a long drive. The next morning I couldn't get out of bed without heavy assistance. I went to the hospital (this was my first lifetime episode of back ailment) and the Kaiser HMO doc knocked my knees with her little hammer, said I didn't have a serious problem, and gave me pills... Motrin, I believe. I needed only one...as is so often my case with pain medications.

Nevertheless, the memory of this has scared me ever since. I have wondered if I herniated anything, etc. I have had occasional acute back ailments, following heavy garden work, etc., over the years, but no chronic pains.

In 2005 and 2007, I received X-ray diagnostics for my back episodes, but my requests for MRI have been refused. Kaiser HMO doc says I get that only in work up to surgery, which is not a consideration here. X-rays show no conspicuous compression. One doc in 2005 said I show evidence of arthritis in lower spine, but since then I've heard "everyone" shows this sign by age 50.

Lacking MRI, I am wondering how I might gain further assurance that my discs are not herniated? Are there statistics available on this subject?

I presently believe my occasional back pains are muscular or ligament -oriented in nature, rather than skeletal. My elderly parents have had more substantial episodes consistent with herniation, etc. I would rather compare apples to apples, though, as aged parents are very different case studies. Hence my interest in this forum.

Any links to reputable statistics would be greatly appreciated. I take solace in numbers, if I cannot get pointed medical diagnosis.