I'm having severe lower back pain. pain goes down right leg and throbbs. have history on protruding disk. why is pain so severe?

Nerve contact...: If the disc protrusion is significant it may be touching a nerve and it can cause severe pain. Different modalities can help depending on the severity if the problem. Physical therapy, back injections, a variety of meds can help keep pain symptoms under control.

Pinched nerve: The disc protrusion puts pressure on the nerve.This causes inflammation and pain. Usually the first step is to try physical therapy and injections .If conservative treatment fails then surgery is an option if the imaging studies match the clinical picture.

It may be that there: Is a further protrusion of that disc or at least a further tear of the outer part of the disc known as the annulus & called an annular tear or both-any of those scenarios may cause increased pain symptoms. One also has to consider other causes of pain in the region & if the pain is so severe you should seek medical attention for an accurate diagnosis & appropriate treatment.