I've had high wbc count for over a year.it started at 13, 000, then 15, 000, 29, 000 then dropped back to 13000.now it is back to 20, 000.

Inflammation: It is a reactive process as a result of infection or inflammation. Since it fluctuates up or down this is normal and okay. You may have some underlining inflammatory process or autoimmune disorder.

Not totally sure: Those are high WBC values for a healthy young woman. You don't mention if you have any other health problems or symptoms that might provide a clue. You also don't mention what type(s) of wbcs are elevated; this could also provide a clue as to the cause. Someone must be ordering these blood tests; what are they telling you? If you're not satisfied with the answer, request a second opinion.