Question
i recently fractured my rib, i am an avid runner/marathoner.  it has been two weeks since i did this.  on friday i tried swimmomg.  i was able to do 8 laps kicking and just holding a board but when i tried to do the crawl i felt some discomfort.

any idea how long it will be till i can/should start running again?

Answer
Any type of fracture typically takes about 6 weeks to heal, but rib fractures are worse; they are never completely motionless because you have to breathe. It's going to take a total of 6-8 weeks for it to heal. You'll have to force yourself to take it easy (I know your type) because an impact exercise like running is going to cause pain if you get back into it too soon. Take it easy with the swimming too, the kicking type exercise is probably ok, but anything with the arms uses the latissmus dorsi muscle, which lays right over that fracture and can irritate things.

There are therapies that can help reduce the pain and help speed healing. In my office we've used electric stim and ice for injuries like that. The patients really like it. Hopefully you'll heal quick so you can get back into your running again!