Digging all over the place?

This is new... Jayce is digging all over the house. Scratching floors, jumping in to my storage boxes and digging, spending excess time in the litter pans just scratching like crazy (he has always been a big digger in those, just more so lately), digging at the food dish now too.
Why would he start this out of nowhere? Hes healthy finally So Im just confused. It wouldnt be a big deal, but his scratching scrapes and makes my ears hurt (like that nails on a chalkboard sound). He has plenty of scratching posts and stuff. Everything else seems to be ok Is he just being his usual weird self?

Scarlett does that all the time. In fact, she is standing next to me in the doorway scratching the floor for no apparent reason. She scratches the walls, water bowl, food bowl, floors and really goes at it in the litter box. I have never figured out why.

They just want to see if they can turn the term "Digging to China" into reality!