What Causes Severe Weakness And Pain In Leg Along With Numbness In Toes?

What can be the cause of severe weakness and pain in left leg, numbness in toes, There is no swelling or bruising, and it does not hurt to touch. Pain occurs from use of leg and getting up from sitting or laying down. The pain radiates from lower back and is mostly on left side. I had transverse myletis about 20 years ago, could it be coming back? The pain started after bending a lot to pick up pecans in grove.