I have really enjoyed the couch to 5k plan and completed it. I'm now trying to run faster for 30 minutes using the Stepping Stone podcast; but I've found that I have started getting pain in either my groin or hip flexor, just the one side. This could be because I've worked hard on changing my running style as I tended to land on my left heel and I've been really focusing on picking up my left foot to land on the ball of my foot. I did a run on Wednesday - it's now Saturday and I've still got a niggling ache. What should I do? I had a Spin class on Thursday, but rested yesterday. I want to go to the gym and do squats and go on the arc-trainer today, but am not sure if it's wise. Any advice would be appreciated. My personal trainer showed me how to stretch my hip flexor, but he also mentioned this can be problematic for runners particularly women and I have to 'watch it'. I am only just getting into running and would be gutted to have to stop/ Any help would be gratefully received; thank you.