Read this article a couple of weeks after starting running for the first time in a very very long time, dont feel so bad at having to stop and walk so much now. IDspite knowing about stetching from my days lifting weights I still have a habit of skipping it and enerally feel it when starting my runs, stiff tendons and muscles do not like the sudden activity.
Only point I would pick up on is the heart attack advice, if you get the symptons of a heart attack which in addition can include severe pain in the middle of the chest along with the high temperature then call an ambulance immediately not your doctor. The hospitals really do prefer it that you waste their time and be wrong than to lay some where having a heart attack because you didnt know for sure if you should call them. Speed is key in treating it!