Suggest Treatment For Pain And Tightness In Lower Back After An Injury

Hi back in 2009 I hurt my leg it felt like the injury was between knee, butt and in the back of leg. For at least a month it hurt to stand or sit or even lay down. The pain was a throbbing type not bad enough to cry . the leg would go through bouts of weaknesses usually while walking and I would have to stop as it felt like my leg was going to collapse. After a while it stopped but the last year or so its been throbbing again and seems to bring low back pain and tightness making walks harder to do. I had my gf lift my leg up to a 90 degree angle and I feel no stretch sensation. So any ideas on what s wrong and how you might fix it.?