What causes throbbing, electric shock pain traveling up spine?

You will probably need a MRI of lower back. Consult a orthopedist and or a neurologist.

Typically, an electrical shock-like pain emanates from the neck downwards if a Lhermitte's phenomenon is experienced. This due to pathology of the cervical spinal cord, like MS, Devic's, B-12 deficiency, and testing should be pursued to uncover causation. Have never witnessed the shock shooting upwards.