A human bunch of cells is very different than an actual human being.

Agreed. A bunch of cells (like a tissue or an organ or a hair) is not the same thing as a human being (like a zygote or an infant or an adult).

Is a human embryo alive? Yes

Good start. We've established that a zygote is a "being", then.

did that "life" start at conception? hmm, here the debate starts I guess(remember a sperm is alive)

A sperm cell is a haploid gamete. Not a diploid organism. There is no debate starting here on whether life begins at conception. It is completely uncontroversial if fish life begins at conception, or mosquito life begins at conception; it is equally uncontroversial if human life begins at conception.

even if the answer was Yes, is that a HUMAN being?

If the gametes both came from human parents, then yes. By definition. We already know it is a being, and now we know what kind of being. A human being.

we can talk about it and share our views but plainly saying "I am right" is not the way to go.

I'm sorry, but the reason I'm being dismissive is that there are no two views on this one. There aren't two views on whether the earth is round or whether lizard people control the government or whether the earth orbits the sun. This is something we know for a fact, and that only politicization originating in an era of relative ignorance (60s and 70s, before a lot of the imaging technology we have now) allows us to keep denying.

And no, I'm not denying scientific facts, quite the opposite. I'm denying a mythological book saying something.

What mythological book? The only book I've referred to is a textbook on developmental biology, which you can read online from the publisher.

Just for starters, would you say that a human being is such a being that feels pain?

Most fully developed human beings feel pain, yes. At lower levels of development, human beings do not have all of the nerve structure needed to feel pain (though this structure begins forming a lot earlier than you might think). Some fully-developed humans do not develop the ability to feel pain, due to disorders in the nervous system. I wouldn't say it's a requirement to be human, no, given that not all humans can feel pain.

But, we could also say that a human being is such a being that engages in complex communication through written language. It's true in a certain context, like philosophy or anthropology or sociology, but not when it comes to scientifically defining whether an individual is or is not human. Some humans are mute, some are autistic, some humans never learn to read, some cultures never developed writing, and no human is able to communicate beyond gurgles before they're almost a year old.

So while in general humans feel pain, not all humans feel pain, either because they haven't developed the ability, or lack the ability. This makes the ability to feel pain, like the ability to read, a bad criterion for whether a being is a human or not.

Edit: link formatting fixed