I don't have many friends in real life.

[Silverobama]

I wonder if "I don't have many friends in real life" is natural if I want to express the idea "I am lonely and I don't have friends to hang out in my life, in reality, in my daily life".

If so, how can I express the idea naturally?

 

[emsr2d2]

I wonder if "I don't have many friends in real life" is natural if I want to express the idea "I am lonely and I don't have friends to hang out with in my life, in reality, in my daily life".

If so not, how can I express the idea naturally?

Your original sentence is grammatically correct but it doesn't express that you're lonely. If that's the case, you need to add that information.
Note my corrections above. We hang out with people or at a place.
You needed "If not" for your question. You're wondering if something is natural. Using "If so" means "If it is natural". If it's already natural, you don't need to ask how to say it naturally.
I don't understand the underlined part. The way you've written it suggests that your life, reality and your daily life and three different things.

 

[Silverobama]

Much appreciated!

I want to say that perhaps I have more online friends than in reality/in real life.

I've met many people online and became friends with them but I've never met them in reality. However, in real life, I have only a few friends. How can I express that idea well? How about:

I don't have many friends in my real life but many online friends.

 

[emsr2d2]

Much appreciated!

I want to say that perhaps I have more online friends than in reality/in real life.

I've met many people online and became become friends with them but I've never met them in reality. However, in real life, I have only a few friends. How can I express that idea well? How about this?

I don't have many friends in my real life but I have many online friends.

See my changes above. You needed "become" because it's attached to "I've". I'm sure you know that "I've became" is wrong.

With my change to the final sentence, it's understandable. You could use "I have more friends online than I do in real life". However, I admit that that doesn't show that you don't have many friends in real life.

If you don't want to use both "don't have" and "have" in the same sentence, you could say "I have few friends in real life but many online".