You may have pain, weakness, numbness, and tingling that runs from your buttocks down the back of your leg to your feet. This is called sciatica. It happens when something is pressing on or bothering the sciatic nerve. This large nerve starts in your lower back. It runs all the way down the back of your leg. Sciatica is a sign of some other health problem that involves the nerve. It most often happens on just one side. Most of the time, sciatica will get better without needing surgery. Treating the health problem that is causing the pain can make this condition go away.