unbearable noise

Do you want to swap? There's a brat above me whose parents are quite happy for him to stomp, run, shout and throw and drop toys for hours on end.

Confused. Is your home connected to another home? Not understanding how you can hear someone showering.

Have you tried talking to the neighbor?

Doubt if much or if anything can be done about noise in regards to someone showering.

Earplugs?

Like the respondent above, I'm puzzled as to how you can hear someone showering in another home. Presumably it is the sound of running water which wakes you so is it definitely showering rather than simply someone flushing the toilet?
Whatever it is, your first contact has to be with the person making the noise. Even if their is someone to whom you can complain, they will not be interested if you haven't first approached the 'offender'.

Unless there is some sort of fault making a loud noise or the person is singing at 4 in the morning, I fail to see what it is you can complain about. This is why I don't live in apartments.

Any one is allowed to shower at whet time they want. Presuming that the 'someone showing' starts work early morning.
No grounds for any complaint or for even speaking the alleged someone!