Wow, you really made an effort here to sound extra condescending. To answer your questions.

We use human neurons for lots of stuff, mainly to research how they work, but also to understand neuronic activities in general. We also have created those organoids for a while, so this is nothing new. In fact, they are so common they even appeared in show The Big Bang Theory.

Second, they can't feel pain and never will. These are HIGHLY specialized cells, who rely on other cells and nerves between them to realize a feeling of pain, and even then they can only process it when they have build the necessary structures, which requires millions of neurons alone. They will never turn into something alive.

You could have just thought about this for a second, but you chose to disparage the work of scientists because it doesn't fit into your narrow moral construct.

Do you understand now?