Sit in your chair with your back tight against the chair back.

后背紧贴椅背。

youdao

Pull your hair back tight, stack two braids on top of your head.

将头发向后拉紧，在发顶扎两条麻花辫团成结。

youdao

It's too tight across the back.

背部太紧。

《牛津词典》

"It's just a little tight back there, but it is what it is, " Strasburg said.

NPR: Nationals Overcome Strasburg Injury, Beat Braves

Ruggiano, originally considered the front-runner to start in center field, has been sidelined with a tight back.

WSJ: Harvey nearly perfect for 4 1-3, Mets beat Marlins

No one said they were cutting back because of tight labor rules and the fear of being sued.

FORBES: In Brazil, Maid Service Becoming Thing Of The Past