It may be, it would be best to remove the heatsink but if you need to put too much force in don't bother - at least then you know what heatsink to use with the CPU! You can always take the CPU off without the Heatsink off first. Not too good though; always try to get it off.
A Knight is sworn to Honour. His heart knows only Virtue. His blade defends the helpless. His might upholds the Weak. His word speaks only truth. His wrath undoes the Wicked.