I have one in my cervical spine. I also used to work for a Neurosurgeon where I learned quite a bit about them. It depends on how severely herniated it is. Is it impinging on the spinal cord, etc. If that is the case and these very severe ones (that required immediate surgery) were not very common in his practice. If it is herniated so badly that it is severely impinging your cord, you can have a variety of symptoms, from foot drop (inability to lift your foot - flex it), severe shooting pain down your leg in a distribution relevant to where the disc is herniated, loss of bowel/bladder control (severe cases only). Milder cases cause some radiation of pain into the legs, but people who are physically active with an exercise program will not necessarily have this as badly as a sedentary person, as exercise helps most mild sufferers. With milder cases, you may also experience spasms in certain areas, as well as pain that sometimes radiates and other times does not, as well as possible numbness or tingling.
I hope this helped somewhat. I have one in my neck and have severe spasms and pain and my pain only radiates partially down my arm at times when it flares up worse than others. I also get severe headaches from it. I have a very small amount of numbness (only detectable on exam and sometimes I notice it when I'm flaring badly) in the distribution of my disc that is herniated. With cervical disc herniations, most patients experience pain in the intrascapular area and traps. This is where most of my pain is. I have had mine confirmed via MRI and it is slightly pressing on the spinal cord, but not impinging it (which is actually more of a total squishing of the cord). I have gone thru PT several times and now just manage on mimimal doses of medications and exercise. I also do stretches everyday and a few other things for it. My doctor suggests epidurals, but I don't want them. I was told I may need surgery in the future if it worsens.