You and your Chester County bankruptcy lawyer may have received a letter closing the Chapter 13 case. This is done after 90 days after the final distribution of the Chapter 13 plan. The bankruptcy judge in the Eastern District of Pennsylvania will have issued a final decree discharging you from your Chapter 13.
But, you or a creditor can request, by motion, to reopen a bankruptcy in the court (it must be in the court which closed the case). If the Chapter 13 is reopened, a trustee will not be appointed by the U.S. Trustee unless the court believes that a trustee is necessary to protect the interests of creditors and the debtor or to insure an efficient administration of the case (look to Bankruptcy Rule 5010 for more guidance).
Again, this rarely happens, but it is important to understand what may occur in your Chapter 13.