What's a place with no worries no fears no problems and no anxiety?

The only place is "heaven "!

if you believe it exists !

I believe that no such place exists, or could exist. If it did, it would be intolerably boring. (That's the problem with the religious concept of "Heaven". You'd be bored spitless inside the first week.)

From an academic point of view you're probably looking for either Utopia or Shangri La, but even those have their problems.

Oz land. Or you're drunk.

The womb.

I can't say 'where' it is, can't say I've been there all that often... It's kind of a mystery... But tequila usually gets me there.

My lanai.

Stress is forbidden here, it is written.