Sadly, the 4D massage chair doesn't massage your past.
Now of course a good massage is going to exist in three dimensions. A 2D massage would just be some pressure on your skin or something. To really get in there you GOTTA work the third dimension! But just think of how great a 4D massage would actually be? You'd start feeling really relaxed and then think "Oh, that's right, I have to schedule my massage for tomorrow." You'd get there already happy and the tension would be dripping away. And then you'd start, and that happy feeling would stretch both forward and backwards in time. The tension of causality would be gone!
We're not there yet. But until we are, this massage chair will be the next best thing.