Actually, whether it "pops up" depends on a few things. If you were actually charged in court, then there would be a record of the proceedings that would exist until you affirmatively seek to have your record sealed. However, if this was a first time misdemeanor shoplift, then you may have been offered a diversion. Most matters referred for diversion are handled out of court and those records are confidential.
Yes. In most cases (unless you received a deferred sentence of some kind) it will continue to appear on your record unless you apply to the court to have it vacated. For misdemeanor shoplifting cases, a person can apply to the court to have the conviction vacated after three years (from the date of sentence).