I'm on Week 6 and have been mostly running on a track through the small woods next to my house. I'm running out of room on these longer runs so I've had to switch to a different route which means running on a concrete path. I'm finding it the hard surface hard work and for the first time my feet hurt. Does anyone know if it's a matter of persevering and my body will adjust? Or should I look into new running shoes? Thanks for any suggestions.