I had a lumbar laminectomy 5 months ago, why am I still in pain?

That is a good one . There can be many reasons including that maybe you should not have had the laminectomy in the first place to that you are out of shape or you never were rehabilitated correctly or this is not your first spine surgery or you smoke, are obese or have underlying medical problems or multiple other sources for your back pain other than the one addressed by the laminectomy. Speak to your surgeon.
Leg or back pain? Back surgical muscle changes scarringi if it is leg pain get a new image.Of your low back i like ct myleograms after surgery postop MRI can be misleading.