What Causes Numbness In The Right Leg Long After A Back Injury?

Hi! When I was like 5 years old I fell down de stairs, it was a small staircase, only a few steps, but I hurt my lower back. The pain was so strong I couldn’t even breathe for a few seconds. I had an X-ray the same day and they said something’s swollen and I would probably feel pain for the next couple of days, gave me some pain killers and said that should be it. So I don’t remember much after that. But as I grew older I noticed that sometimes my right leg goes numb. It never was really bad or something, but a year and a half ago I started working somewhere that requires me to stand 8 to 11 hours a day and I can’t move much. Since I started this kind of routine, I noticed that the pain is worse every day and that my leg goes numb really often, to the point where it almost hurts. I was thinking about seeing my GP and then I’ll go from there. Do you have any advice or something that can help me figure out what this is? Thank you!