Rule of thumb - (not a rule - just rule of thumb) most dairy products don't freeze well. They tend to lose their texture.
Milk, cream, etc, will 'keep' when frozen, but will separate and appear curdled. They are still good and completely usable in recipes, but probably not satisfactory for drinking. Cheese can get rubbery - still usable, but not for plain eating. I buy a quart of buttermilk for baking, use what I need and freeze the rest in 1/2 cup comtainers. It is still fine in baking, but you probably wouldn't enjoy drinking it.
So if you want, you could freeze sour cream, but when you thaw it, you won't have that smooth creamy texture anymore. It will be OK mixed into a recipe, but not great served on top of a baked potato.