Suggest Treatment For Pain In Legs And Knees After An Injury

Hi I m 16 years old and I fell on my knees while running two days ago and got scrapes on both knees. I didn t think much of it until my right leg started hurting a few hours later. So when i lay my legs down in no matter what position i put them , with my legs up or down or to the right or left side, it still hurts and feels heavy especially in my right thigh. I thought i was just sore at first from practicing with my team or from my fall, but now i cant bend my knee because of the pain and have to walk with my leg perfectly straight. What should i do?