It's a well known fact that when the oil is cold, the plates stick together and it requires initial effort to move the bike while in gear. Give it another shot. Like someone said, try rocking the thing.
For the same reason, when I start the bike with the rear on the stand and in gear, you pull the clutch and the rear continues spinning. I extend my leg and with a foot try to stop the rear and it takes some effort. But once the bike is warm, no issues. So, if the problem disappears when the bike is warm, then it's just stickiness of the plates. If you have the same problem moving the bike when it's warm, then it would seem you have a real problem.
Let us know.