Any idea why the insides of my knees have started to hurt? I went out on Friday and did 5k and for the first time in a year of running my knees started to really hurt after the run. They haven't been quite right since so I've rested since Friday but they didn't feel too bad today so I've just been out again for another 5k. Just got back and they are really hurting again. I'm sat here icing them but no idea why this should suddenly start happening. The pain is on the side and the bottom of the knee cap on the inside of my legs. My route is the same and shoes etc haven't changed. Any ideas?