So I have a German passport,and i want to live in the UK, is that possible? Or do I have to get a visa, or something like that?
As long as the UK is in the EU, you can live there without visa. What happens when Brexit takes effect is not certain, but in all likelihood you will require some sort of visa. Having been an UK resident prior to Brexit may or may not help you get that visa afterwards.
Brexit negotiations are ongoing, but it is a good guess that it will happen by March 29th, 2019.