Is it ok to have pain 8 months after a discectomy? what kind of pain and what level is acceptable at this stage?

Yes and no: Back pain after surgery for disk problems is not uncommon. Microdiskectomy only deals with pain related to nerve compression (sciatica). It is not the intent of this surgery to treat back pain. If you are having pain, this could indicate degenerative disease, infection, instability, or inadequate surgery for the problem. All of these would need to be addressed by your operating surgeon.

There is a 5-10% f: Failure rate especially if one is a smoker and if the back pain was more of a component than the leg pain suggesting that a fusion should have been done. In 1-2% of patients, nerve pain can develop related to post op changes. The rate of a recurrent disc herniation is 5%. Some studies suggest when surgery complicated by spinal fluid leak(1%risk) lower success rate as well.