Lower Back pain on left side and right foot numbness

I got in a wreck when I was 16, I am not 22 and recently had my first child. I have had reoccuring lower back pain since the wreck, mainly on the left side. It normally starts out as a dull pain which gradually gets worse, and turns into shooting pain down my left leg. I have ben seen multiple times and everytime the doctor gives me muscle relaxers and pain killers and sends me on my way. Last weekend I was doing squats at drill and went down to squat when all of the sudden my left leg gave out, which was followed by SEVERE pain in my lower left back, the pain shot down to where my butt and leg connect. I was seen at the ER the doctor gave 5 x rays. He said that i my spine is TOO straight, meaning i dont have any natural curvature in my back, and I am experiencing muscle spasms which are causing a pinched nerve. I have ben experiencing this pain for a few days when I also started feeling numbness in my right leg. Is this caused by the same nerve? Is it possible to feel pain on one side and numbness on the other from a pinched nerve?