I am only in week 3 of the couch to 5k plan. I have been loving it until last week i decided to go a different route, some where more uneven under foot, and came home with painful knees. The pain is the same in both knees, and feels like it's under my kneecaps. It hurt when i ran after my children in the park, and when i went up and down stairs. I left a two day gap before going again (back on the flat this time). My knees were painful. I saught advie from my pilates teacher who recommended getting fitted for running shoes. I did (feeling a little poorer now). The man in the shop, having analisyed my gait on the treadmill, said i had fallen arches, which could well be contributing. I left it two days again, to give my knees time to get better. I've just come back from a run (session 2 of week 3). My knees hurt straight away. My stride feels all wierd. I saw it through to the end, which perhaps i shouldn't have done. Please help! What can i do? Should i rest a whole week? Am i just not built for running?