Hi! I am a 30 year old female, about 40 pounds overweight, who just began a walk/run program based on the book, The Beginner Runner's Handbook. This is my 2nd week/5th workout and I walk 4 min. and jog 1 min. for 40-45 minutes. Last night my knees really hurt. More on the inside front. Not sure if it is muscular/ligaments and just general soreness from being overweight and not working out in a few years. Any ideas on stretching or helping ease the pain? I have really good new shoes to support my arches...so shoes shouldn't be the issue. Thanks for the help and support!