Stress fractures are usually the result of altered biomechanics, which means the structures of the foot are either mechanically not stable and/or the bones of the foot are subjected to repetitive micro trauma.
Example: a mildly pronated (flattened) foot in normal conditions would not develop a stress fracture, but a runner with a mildly pronated foot could very easily sustain a stress fracture by repetitive usage on an altered biomechanical foot.
Stress fractures usually take time to develop and the symptoms are pain, redness and swelling. X-rays are usually only positive after about three weeks of symptoms. In some cases, a bone scan is necessary to make the diagnosis.
Again, treatment for this condition, like most conditions of the foot, requires immobilization, ice and compression. Orthotics are the best treatment for long-term control of stress fractures. Immediate control would consist of a cast boot.