Yes and no.
It’s not hard in the sense of having to learn it in the way someone learning English as a second language does. We learn our “palette” of sounds along with our first language as kids.
But there are plenty of things we mispronounce, just like, I’m sure, people in your native language.
A couple of years ago one of my clients pointed out I was pronouncing the word “taciturn” wrong (taKIturn). I’m not sure when or why I picked up the incorrect pronunciation – but of course, as soon as I realised it was wrong my pronunciation simply changed (and no, it wasn’t difficult to do).
Being a “native speaker” means being completely unconscious of the way you use language. And yes, that means unconscious (most of the time anyway) of the imperfections, too.
My speech is full of imperfections.
No excuses or explanation — because I honestly don’t see why justification is necessary.
Humans are wrong about most things most of the time. Who cares if I make a mistake with my English.
But, and this is the important part, herein lies the paradox of language learning. You go to school and English classes focus exclusively on accuracy (it’s easy to measure, after all). Yet in reality, there is no true “accurate” model of English because the English I know is a collection of my own (often flawed) experiences.
And my experience of life (and therefore English) is very different to anybody else’s experience.
Of course, the concept of a “standard English” exists.
But that’s all it is.
As an aside, a great exercise for developing good pronunciation—particularly rhythm and good “chunking” skills—in English as a second language is “Shadowing”. I’ve got a free guide here, for anyone who wants it.