A stress fracture of the lower leg is generally considered an overuse injury. They are sometimes difficult to diagnose due to vague discomfort and generalized pain over the muscles of the lower leg and are often misdiagnosed as shin splints. They come on slowly over time from cumulative trauma to the muscles and bones, often due to overuse. They occurs when muscles become fatigued or overloaded and can not absorb the stress or shock of repeated impacts. Fatigued lower leg muscles transfer that stress to the nearby bone and the result is a small crack or fracture in the bones of the lower leg.
treatment:
The best treatment for a stress fracture is rest. Taking a break from from the routine and doing some low impact exercise for a few weeks (six to eight) can help the bone heal. If rest isn't taken, chronic problems such as larger, and more persistent stress fractures can develop. Re-injury may result in a chronic problems, broken bones and fractures and the stress fracture might never heal properly.The following advice may protect you from developing stress fractures in the first place:

Progress slowly in any sport. Gradually increase time, and intensity, running mileage or effort and follow the ten percent rule.
Eat well, and include calcium-rich foods in your diet, especially if you are a female athlete.
Use the proper foot wear and replace shoes when needed.
If pain or swelling begins, immediately stop the activity and rest for a few days.
If continued pain persists, see your physician.
Any leg pain that continues for more than one week should be seen by a doctor for a thorough evaluation and diagnosis