finished main quest what would anyone suggest to do now??? pc thanks for ur help everyone

PC version or Console version?

Skyrim = so many possibilities. Have you joined any guilds? Or walked from one side of Skyrim to the other and explored every place you come across? Your Dragon Born so, go through every draugr crypt you can find and look for words of power.

Try to find all of the Daedric quests. They're some of the best in the game.
Get and complete the Dawnguard and then Dragonborn DLCs. They compliment the game well.
Do the civil war (*whispers* "as a Stormcloak" ). It's a major part of the game's conflict.

Join a faction and do all the relevant quests.