Should I go check with a doctor on my knee?

[CFC4Life]

Today, leaving from school...I was riding my bmx bike through a parking lot. Somehow ( it happens often when I put these shoes) the showlaces got tie around pedals. So I stop pedaling to slow down so I could untie it but once i did..I was barely looking up and then all the sudden I crashed on those edges of a sideway ( the edges that have like the red line where not to park) and I fell forward luckily I was able not to my face but my hands got all scrappy-feeling. First thing I felt was a pain in my left knee. I think it hit hard on the ground. It still feels sore or hurting a bit. I can move it normally but when i put my knee as far as it can go back it hurts. somewhere under the knee cap I can feel it's hurting. Any ideas? More info? I feel like flat except my facce didn't touch the ground.