I am getting an mri on monday of my spine, the left side of my back is always swollen, numb on the outside, but hurts inside. any ideas?

Muscle and nerve issue: The MRI will show the status of the muscles, spine, and nerves. What you're describing is due to irritation and inflammation of several of those structures. Could be due to a bad disc, poor posture, injury, or a variety of other mechanical factors. The results of the MRI will guide recommendations for your condition, which could include medications, physical therapy, self-directed exercise program.