Why is my MacBook Pro making this noise?

I just recently got this MacBook pro as a gift. I keep noticing this I’m thinking it’s just the fan because it sounds like the fan. But I just got this mac and this is my third day of having it. This is my second time actually using it. Is it suppose to make this sound? It’s not a really loud sound, but it is bothering me. Maybe I’m just being paranoid. Like I keep thinking “What if they sold me a used/refurbished mac when I actually bought it for new”...“I wonder if anyone else’s mac makes the same noise” just stuff like that. I mean isn’t it suppose to be silent? Oh and every time I pick it up or slant it the sound gets louder and more noticeable.