Hi thanks for the query.
Since i had not seen the x rays i could not comment on the stress fractures
. But if there is unaccustomed long distance running there could be micro stress fractures which cannot be picked up on x ray. Since running 4 miles if you had not regular runner it could give rise to some form of micro stress fractures. It can be seen mostly in fresh military recruits or fresh recruits in sports. I advise you to start slow pace jogging and slowly improve the intensity and along with use of good sports shoes.