I agree with Sarah – some of this may be elevated due to the post surgery hormone boost. Also, bunnies may react to discomfort or to having an unusual scent on them, (from vets, vet techs, all that was associated with surgery), by digging and/or marking. The marking should settle down and the veracity in which your bunny digs or chews on things may settle. But if your bunny was a digger prior, then I also agree, you just may have a “digger”. Just part of the the bunny’s personality. I have a digger currently. She will chew, dig and move blankets around, she will dig at hay, dig at the floor, dig at the couch if given a chance. (And she’s at least 8 years old)
Here are some solutions I have found — not to stop digging, (as she enjoys it), but to help redirect it.
Litter Box Digging – I have a screen that I put over the litter to prevent her from digging out her litter box. Some people have been successful with covered litterboxes.
Blankets to Destroy– IF your bunny doesn’t consume cloth when digging and chewing, then this is a great way to wear them out. You have to REALLY watch/supervise to make sure that is the case as consuming a bunch of cloth would be very dangerous. My bunny chews a thousand little holes in blankets making blanket confetti out of as she does this. Then she pushes and pull, digs until she flops in exhaustion.
Make a Diggy Box: There are several ways to do this. I like just getting a plain cardboard box, cut out two entrances and add shredded paper. If you bunny is likely to pee in the box, then you might find a small plastic laundry basket instead of using a cardboard box. It can be a bit messy as the paper comes out of the holes, but it does let your bunny get out his diggy instincts.
I know there must be others here who have “Diggy” bunnies. They may have more suggestion.