SO i am doing C25K and loving it. I am on week 6... I have had issues with my tendons (achilles) before and never  been able to run, but the slow progression of the C25K hasnt hurt or strained my tendons. 
However - the lower part of my leg, to the side of it, starts to hurt really badly when I run... I did my 20min run fine a week ago, but now at about the 8min mark my leg hurt so bad i cant even walk for a little while... it goes away in a few mins... 
ANY ideas what is going on?