First of all, keep in mind that I am unable to diagnose you because I am unable to examine you, this forum is for educational purposes.
The pain in your left calf and subsequent back pain may be due to a pinched or irritated nerve (pain from a L5/S1 nerve root would be felt or 'referred' to the calf area). When there is an annular tear then some disc components can leak out and either compress or irritate the nerves. Many people without out any back pain can have findings of annular tears, compressed discs and bulging discs on MRI. Thus it is unclear who will have diabling pain just from an MRI. I would suggest an EMG of the left lower extremity to evaluate for signs of radiulopathy (damaged nerve root). Conservative therapy with physical therapy, pain medications (NSAIDS and sometimes narcotics) along with epidural steroid injections are usually preferred for the first line of treatment. If after 6 months of conservative management, you are still having significant pain, and functional limitation then you should see a surgeon, neurosurgeon or orthopedic spine surgeon for possible disc fusion surgery.
I hope this has been helpful.