(Found by my good friend DxBxD IDGARA)

I've seen a lot of people have an issue where they are locked out of breezehome and proudspire manor after completing the Civil War on the Stormcloak's side. People have recommended becoming thane again, talking to the steward, ect. but to no avail. People have even restarted their characters simply because they locked their dragon priest masks or other essential items in their houses. And that svcks. So, to anyone that has this problem, here is how you get back inside your house:

1: Find your spouse (or marry someone)

2: Tell them to move to the house that you are locked out of

3: Fast travel to the location of your house

4: Press back button and wait for a few hours for your spouse to arrive

5: It will now be unlocked once the spouse goes inside

Now, this problem is caused by YOU! Yes you. A way to prevent being locked out of your house is to NEVER STORE KEYS. EVER. ESPECIALLY IN THE HOUSE THAT IT BELONGS TO. It's like real life. Hope my friend (and I) helped those having trouble with this!!