I sided with the imperials and the war is over and the jarl says i can buy the house but the steward says it is unable to be purchased due to unpleasantness....what do i need to do?

Have you done the Blood on the Ice quest?

Otherwise, you may need to wait a few days in game before it's avalaible.

no i havent the war is over and i finally found out that you can get a house in windhelm so i went to the jarl and he said talk to the steward and all he says is its not ready..what i need to do/

You need to do the Blood on the Ice quest first, the house actually comprises part of that quest.

The events of that quest are the unpleasantness the Steward referred to.

Have a look around the graveyard, talk to guards etc. After you travelled to and from Windhelm a few times a scene occurs in the graveyard.

thanks i got it now.