Hello everyone. I am a newbie to this site and need some help. I am have been inactive for a year due to neck injury and want to start a running program. My aim is to run a 5k by Sept 24th. I have just started, a week ago, an app I found on Apple for learning a 5k- 3x week 5 min brisk warm up, than 1 min run, 1 1/2 min walk for 20 mins, finally cool down. Week 1- Changes after that. Prob is sometimes I have more than 2 days inbtwn program and having hard time breathing toward end of 20 mins. What to do?