Knee Injury

Hi

I was playing football a couple of weeks ago and jarred/twisted my knee. The pain wasn't that bad as I was able to carry on playing quite happily for 25mins til the end of the match. That evening my knee began to tighten but not really any pain. The day after my knee felt swollen below my knee cap, at the top of my shin but didn't look it. I had to control my stride when i walked as if I swung my leg too far it hurt just beneath my knee cap. As if i swung really hard there would be nothing to stop it swinging back on its self. It is easing off now but I still can't swing my leg fully. It doesn't hurt when i side foot the ball (controlled) but it hurts when I shoot (final section of the swing of my leg). Does anybody know what the injury is? And how I can rectify it? I hope the above makes sense. If you need any more info let me know.

Thanks

Alex