Need to control flat feet.Also use counterforce shin brace.Also make sure your nutrition is adequate.Sometimes poor nutrition results in low calcium in the bones which could result in a stress fracture

Modify distance and speed of running. try to run on grass or track ( less impact) proper shoe ware and stretching prior . nsaids and voltaren gel (OTC in drug store). if still an issue see an orthopedic surgeon to make sure you do not have a stress fracture.