Yep to what EveJ said! The running stores will also video tape you running for about 20-30 seconds to look at the way you run. Getting in the right shoe based on the way you run will make a *huge* difference. My hubby is a big guy and a runner. He finally got orthotic inserts for his running shoes to correct his over-pronation and it is making a big difference but he has already done some damage from not starting out the right way and getting it checked and corrected early enough.
I am currently on week 11 of working out. Those first few weeks were the hardest but now I'm hooked. You just have to have time set aside and do it! I know I have to get up and do it before my day gets going or it's very tough to try to fit it in later in the day or evening.
I have been using the Nike + GPS app on my phone when I run. It's got some great features that help keep me going while I'm out there huffing and puffing lol