through the mill

"through the mill"というフレーズをご存知でしょうか。

苦難を経験する、というような意味です。Collins Cobuild Dictionary of Idiomsの定義を引用します。

If you go through the mill or are put through the mill, you experience a very difficult period of situation.

"mill"というのは工場という意味ですが、ここでは製粉所のことです。

粉挽き（製粉機）にかけられる痛み（！？）を苦難に例えた表現ということなのですが・・・。

EUGENE, Ore. -- Oregon is fully reopened as of today, and that means most COVID-19 restrictions are lifted. 

It also means local businesses now have more freedom to do as they see fit as far as mask mandates and social distancing guidelines go. 

（中略）

One Eugene resident, Bruce, said he will still use some caution and carry his mask wherever he goes. 

"Relieved, confused, disoriented, all of that. And I'm pretty sure I share that with everybody else. We've all been through the mill together and we are hopefully emerging out of the other side of it," said Bruce. 

(Oregon Reopening Gives Businesses More Freedom Over COVID-19 Rules. KEZI-TV. June 30, 2021.)

パンデミック・・・、まだまだ苦難は続きます。