Personal story is usually not appropriate for a statement of purpose. Some universities may have an optional diversity statement. But in general, econ PhD programs do not care about applicants' personal background. There will be an advantage for under-represented minorities (Hispanic and black, basically) and women, but this information is usually provided elsewhere in the application.
The emphasis of a SOP should be research experience and research interests. This usually includes indicating a few faculty members you want to work with, but this is not strictly necessary.