If the answer to the above is "yes" then check out this site, it may just be a question of adjusting your shoe laces.
Do you get cramp in your feet when running? - Couch to 5K
Do you get cramp in your feet when running?
There's a good video guide on Runner's World too - I was suffering from a slight bruised feeling on top of my left foot and it's gotten so much better since adjusting my laces! I was skeptical but it helped! runnersworld.com/running-ti...
I've found this a reeally useful tip as I have quite wide feet and need looser lacing. There's also a way of doing parallel lacing rather than cris-crossing that takes the pressure off the top of your foot. I found it on You-Tube. Both things help, though even with really wide trainers and super-tied laces my feet still get a bit numb.
Thanks for posting this link. I have no plans to run a marathon, but the advice on how to run efficiently was very interesting and I might give the belly breathing a go ....