Nobody can answer the question of whether you were "misdiagnosed" without knowing the basis of your Dx and seeing your full chart of tests. There are plenty of people who appear to be properly diagnosed but who do not have visible lesions on an MRI.

I was interested by this: "Previously reported right frontoparietal lobe subcortical hyperintense STIR weighted signal intensity is not seen on the study." It sounds like maybe there was a lesion or some sort of hyperintensity seen in the previous study that was not present this time.

As for the spinal MRI, nobody can tell you whether what they are seeing in your spine is causing your symptoms without knowing what your symptoms and and doing nerve conductions studies. However, the C5-C6 statement that flattening of the spinal cord is seen means that the spinal cord is being affected. Whether that impingement translates to pain or numbness depends on how severe the flattening is and how your body has responded to it.