I hit my left knee on the inner portion of the patella After a few minutes a big bump showed up. I iced it. A few days later I experience intense pain in my left side lower back. The pain increased to the point that I began to limp, unable to put weight on my left leg. Burning sensation on the left thigh began and intense pain made it impossible to walk. What muscle/nerve runs from the knee to the lower back and groin area?