The pump is a circulating device as you know and depending on your system
set up will run as long as circulation is needed.
If you are fully pumped then whenever the boiler is running so is the pump
(most instances) if you have a gravity hot water system then the pump will
only run if central heating is called for.
This is by no means the total answer as you have not provided all the
information but should help to solve your problem.
One thing is certain if the pump runs when the boiler is not lit & the
programmer is set to Off you should investigate further.