What recourse do I have in continuing to pursue my claim through worker's compensation?

I was injured in a car accident a year ago. I had an MRI scan and was diagnosed as having spinal stenosis and disc herniation in my lower lumbar. I have been under treatment for these injuries to include pain management by injections. I recently fell at work with in the last month and reinjured my lower back again. The worker's compensation adjuster sent me to a clinic in their network and the clinic doctor ordered an MRI. The radiologist for the most recent MRI reported that I have no signs of any damage to my lower lumbar area and no signs of stenosis. I feel that there is a huge discrepancy between the 2 reports. The current doctor for the clinic states since this recent MRI shows no signs of any damage, I should be able to return to work but I'm am still in pain.