What Causes Pain And Numbness In The Buttocks And Legs?

Hi, I m in the building/civil engineering trade, hands on. About 6 weeks ago I felt a ping in my lower back while doing an awkward heavy job. My left buttock, and down my left leg became painful day and night on and off through the next few days. With pins and needles and numbness in my middle 3 Towson my left foot. Not really knowing what position was most comfy for me. My back just gave me lower backache. The pain eased after the first week, but is still there in all areas, with my foot still feeling exactly the same. After 4 days I visited the doctors, whom said I d agitated a nerve in my back. I was given cocodomol for pain relief. Do this/these problems naturally go away, or do I need to see a specialist or some kind of manipulation? Do I need to do specific exercises? Thank you. Kerry