Look online for a "dermatome map." This will show you which spinal nerve innervates which area of the body. The MRI indicates that you have likely nerve compression at both the L4-L5 and L5-S1 levels. This pain often feels like what is commonly called "sciatica." (pain running down buttock and back of leg).
I would suggest you make an appointment with a spine specialist if you have not done so already. This could be a fellowship-trained orthopedic spine surgeon or a neurosurgeon whose practice is limited to the neck and back. This is the best place to start for an accurate diagnosis and plan of treatment. You will probably be referred for a course of physical therapy and conservative treatments will be tried...oral medications, perhaps a series of epidural steroid injections, etc. Surgery would only be considered as a last resort, after conservative measures have been tried and have failed...despite the word "surgeon" in the doctors' title.