¿Cuál es la diferencia entre „uczę się” y „się uczę” ?Puedes dar oraciones como ejemplo.

„Szybko się uczę”
„Nigdy się nie uczę”

In these sentences "się" is not after the verb because "się" at the end of the sentence doesn't sound right. When it's in the middle of the sentence like in sentences 1 and 2, it's ok. But in the sentences 3 and 4 the verb is at the end of the sentence so we flip the positions so that "się" is not the last word.

There's one more rule. We cannot start the sentence with "się" either so if the sentence is 2 words long eg.: "Uczę się." and that's all, then you leave "się" at the end because there's no other place you could possibly move it to.

To sum up:
Don't end the sentence in "się" unless you don't have any other choice because the sentence is 2 words long.