Four days isn't very long
It takes them about two weeks to fully settle in a cage and develop habits and decide where to nest and make hoards and pee etc - and also to scent mark it. During that two weeks it is best not to clean them out or it sets back taming and really stresses them.
You could just try talking to him through the cage or adding the odd treat. They often don't like a hand in the cage at first though (and can run at it) until they're more settled. Especially a tank if the hand comes from above.
Does he have plenty of substrate and nesting material? (plain white toilet paper torn into strips for nesting material). Some hamsters are more vocal than others but he will be a bit scared if he's just settling in - and testing things out.