"Next to you" is a common way to say "beside you" or "near you" in Engpsh. Here are a few more examples:

"I'm sitting right next to you."
"The store is just a few blocks away from us, so it's pretty close by."
"I'll stand next to you in case you need any help."

If you want to describe someone or something as being close by or in the same location as you, you could also use the phrase "by your side." For example:

"I'll always be by your side, no matter what."
"I'm never alone when you're by my side."
"Don't worry, I'll stay by your side until you're feepng better."