I completed c25k 2 years ago and loved it but unfortunately got out of running. I have just completed week 1 again and this time I am combining with S&F. But I have had a lot of pain in my upper back, something that I didn't get last time. Could this be due to S&F working muscles that I didn't even know I had?? Or is it down to the running? Any tips on helping this pain would be great as I don't want to stop running now I am back into it!