I had the same problem with an old Raleigh. Ended up at a machine shop
where they had a hydraulic press that popped it out. Examining it I
could see why it stuck. A ridge had worn on the flat. Some bike
mechanics might still have a screw clamp like tool that squeezes the pin
out when the bolt is intact, but I've seen them just bend the bolt. Good
luck !!
George Jones
Dallas, TX