In your F specs you are defineing the file as an Update file. The default then when youi read a record is to lock the record. You need to either execute an instruction to unlock the record or when you get the record with a READ or CHAIN you need to read it without the lock. READ(N) or CHAIN(N),
Now with that said, when you actually want to update the record, you need to retrieve it with out the (N) else it cannot be updated.