Hello, I've just started having pain on the outside of my right knee I was playing boo with my son when I first felt a sharp pain, over the week each time I kneel down I feel a hard throbbing pain, when rubbed it throbs and also when bent, when the leg is straight it's fine! My knee clicks now and again and when I feel the knee cap it feels like it's grinding, does anyone have any ideas what this could be, my partner seems to think it could be my cartilage!