I'm a newbie and just finished Week 1, Run 3. I really enjoyed the first two runs but during the third I started having pain and stiffness in my calves. I did a few stretches and the brisk warm-up beforehand so I'm not sure why this pain now? Where I run is not the ideal place as it's quite hilly with a stony track, could this be the cause? I have so much motivation at the moment, I don't want anything to put me off. Is there anything else I need to do?