Why don't we have "en rast" here? Would that be correct?
We just say "ta rast" (take a break) and "ha rast" (have a break) in Swedish.
That's true. I just want to add that this is not the only case where we don't (or prefer not to) use an article. Lundgren8 wrote something interesting about this here: https://www.duolingo.com/comment/5824774
What about "en paus"? Do you use it in everyday speech?
I put that and it was accepted.
Can we say NU HAR VI RAST or just vi har rast
That works too (added it as an accepted answer, it was missing).
fika refers to something you may eat and drink during a break, not the break in itself. Though we do talk a lot about fikarasten, the most important part of the work day :)
fika more important than the work itself
Yes, because Swedish coffee is THE BEST. And everyone has a right to coffee breaks. :)
What about : "vi är på rast nu"?
Is Vi vilar nu wrong?