Notice how hardly anyone has recommended an entire piece?
That's because classical music ain't very good at the soothing. Or it is, but only for short times. Indeed, most of it is characteristically mercurial; part of its charm.
If you want soothing, why not step outside the classical world entirely and just get some stuff designed to sooth. It's pretty awful, I think, but to each his own.
Even better, get yourself a nice kitty. Kitties are soft, and furry, and very soothing. A nice hot bath is good, too. And a back massage. Why use music for those purposes? Music's for listening to, paying attention to. That's like using a thoroughbred race horse to plow the field.
Race horses can pull plows, but what a waste!!