C25K-ing here too – just done the first run of week 4 (well, 2 days ago) but I have had recurring problems with the tendons/small bones in my big toe which I have just learned is called sesamoiditis (although it happened whilst gardening rather than running), so I am with you on the pain thing V8!
I am terrible for not stretching so am going to just do that for the rest of this week and then pickup the last 2 week 4 sessions next week and get back on track.
I am so not a natural runner being more of a mobile mountain than anything else ;-) Just trying to actually complete the whole program for the first time this go – I have generally got to this stage and injured myself then given up, but I am determined to finish this time!!!
The long term aim is to move the running to once/twice a week (sticking around the 5k distance), do a bit of gym to try and fix all my biomechanical imbalances and start getting a couple of rides in a week on the mountain bike too again (neglected largely since my last injury a couple of years ago).
And loose some sodding weight! Since I started running and without consuming more I have gained weight although lost body fat (2.7kg on, 3%BF lost). Going by my past experiences of exercise this happens to me then the weight suddenly falls off whilst I am not looking!