I have a white blood count of 14.2, what would be the reason for this?

Leukocytosis. A high white count (leukocytosis) can be caused by many different things, most commonly an infection. Some people have high white cells due to a medication they are taking. Others are born with it. Others develop it because of dangerous conditions such as leukemia. Please consult with a hematologist to determine what form of leukocytosis you have.
See below. Welcome most common is infection urine or sinus or lung or any infection less likely is blood disorder see your doc for work up and treatment.