Quoting Mrs. Cartman:" So yesterday I started running for the first time in four years, three rounds around housing and I was ... [snip!] ... in this case, with this amount of pressure. Should I push through the pain or wait a couple of days for my muscles to repair?"
The more you do it, the easier it gets. Took me a week after I started jogging for my body to not feel like it is dying.
If it hurts too much to run, just walk at a fast pace...just until you build up that routine of doing it everyday. Once you stop for a day, it is hard not to put off another day and so forth. If you can't walk, even, find something else to do that will work you out. ((Yoga day/wii fit/etc))