In addition....
Start slowly. Make sure you are healthy enough if you have not seen you doc recently.
Go to a running store and get fitted with a good pair of shoes that will work with your gait.
Keep your runs conversational - or at an effort that you can carry on a near normal conversation if you were chatting.
Be consistant - run 3-4 times a week - no more than 6
Soon you will see that an investment in tech clothing will help you feel better on the run. Cotton will feel like it weighs a ton and it can be abrasive.
Find a training plan. Galloway is a great place to start for a half...you may need to begin with Couch to 5k first. It depends on your current fitness level.
Log you miles. Note how you feel, what you ate, the weather, anything that may help you when you look back.
Smile! - seriously look at folks you meet and see how many are grimacing or not smiling. A smile will knock the stress down and help keep you relaxed.
STRETCH! after every run, save 5 minutes to stretch out your body. Calves, hamstrings, quads and hips.
Most of all, have FUN!
