Just done W2R3, my left leg from the knee down felt like it was burning from the very begining of my run today, I felt like I neededto stop and give it a good stretch! I didn't I carried on to see if it would ease of which it did slightly but every time I had to do the 90 mins of running it was hurting again. I was running on the treadmill at 7.5 so not exactly going fast. any ideas what this might be??? not done running before so not sure if this is normal? I feel like my confidence has been knocked a bit and am aprehensive about moving on to W3R1. It doesn't hurt anymore. any advice?