Assumption theory may apply. (make ass out of you & me) You do have a jack under the bike, right?
#1. Jack bike so that tire is off the ground.
#2. Then let jack down as to let rear tire rest lightly on ground.
#3. Should free up axle. If not , possibly left wheel bearing trying to sieze to axle. You will have to punch it out.
#4. Once out check for scoring of axle & bearing race.
#5. Remove any scoring marks or tool gouges.
#6. Check that axle slides freely thru all common parts of assembly ie. spacers, bearings, differential housing.
#7. Apply grease liberally to axle on reinstallation.