There are 3 things a child has control over---eating, sleeping and elimination. So when you see a big change in one of those areas--you can guess that stress is playing a factor. A child is trying to establish a sense of control in an otherwise difficult situation. On top of that--- 4 year olds are typically "out-of-bounds" and push limits in ways a parent finds amazingly annoying and over the top. Has it occured to you that he could be literally "pissed off" about something- and trying to find an outlet. The combination of age and stress could be what is causing this acting out.
I would handle this in a very matter-of-fact way. Allowing him to clean up his own mess without yelling or freaking--simply handing him the supplies and letting him know that if he's making the mess--he's cleaning it.
Additionally some things that might be helpful is finding 20 minutes a day to dedicate to him for "special time", allowing him to make more decisions/choices, giving him some outlets to release tension (bike riding, water play, play doh, swinging on the swing).
Good luck and the nice thing about being a parent is knowing that these things do pass.