Freezing sour cream does ruin the sour cream especially if all you want to do is eat it without using the sour cream for cooking or baking with.
When you freeze the sour cream it will take on the texture of cottage cheese and won't be as good to eat or good tasting and will not go well with chips and other foods you want to put the sour cream on.
However the frozen sour cream will still be safe to eat and does work great for cooking and baking with.
But I would only freeze sour cream if all I was gonna do is cook or bake with it.
Otherwise I would just refrigerate it and eat the sour cream before it went bad.
Sour Cream will remain safe to eat for up to 3 weeks past expiration date as long as it's kept refrigerated and that is for both opened and sealed sour cream containers.
As long as you keep the sour cream in the refrigerator it will be safe to eat for 3 weeks past the expiration date.
If the sour cream smells bad or has mold in it then throw it out.