But the pain isn't in the hand. Pain is in the head, caused by signals which normally come from the hand, and results in feelings that the head places onto the hand. So phantom pains in amputated limbs are caused by real things. Maybe the nerve that use to communicate the pain from the hand is sending in a false signal due to another reason. Maybe something in the brain is misfiring and some other sensation from another part of the body is registering as pain in the hand. Even if there is no outside of the brain cause for the pain, the brain is still feeling the pain so there is still an actual problem, just one with the brain.
So while there might not be much to do if the brain is just crossing signals incorrectly for a couple of days, I would still suggest significant pain be checked out and a doctor you are paying should help look into it.