Managed my first 5k in just over 37 mins on Tuesday, felt great afterwards, but hurt my back on Wednesday lifting my daughter awkwardly into the bath. I've never had back problems before - could it be connected to the running? I haven't run since, but might give it a go tonight, just a slow easy pace.
Thinking about it, I took a new route on Tuesday which included running down a great little (but steep) hill. Could this have something to do with it?