I'm in my early 20's. I have back problems and weakness in nerves. If my back hurts, one of my leg and knee would hurt too. I have seen doctor for it before and it's been 2 years ever since that. He told me to continue exercising certain exercises. I still do them but not all of them, I blame my lazyness and low will. However, I still continue to do a few of them during the past 2 years. Recently, whenever I get out of the car my back and leg would hurt, and then I can feel the same pain once I lie down on bed. I sometimes have to stay long in the car because of traffic and also I would sit long as I work on computer, once I get up I get this pain and sometimes I feel like I'd not be able to walk, until I walk for a bit more I'd be like okay again