^^^^^
+1
They have attached themselves to the sockets via heat and time...
Some bulb socket grease make the job easier in the furure...

 

Yes, 1/4 turn to the left or counter clockwise and they will come out. Had to use plyers on mine too. Also, puting them back in you may have to use the plyers again because they go back in just as hard as they come out.

 

i did not have this problem when changing mine out. mine snapped in and out very easily.