with you back against the wall Meaning   in a difficult sit | English Choice

with you back against the wall

Meaning
  in a difficult situation without many options @engchoice

For example

 I wish I could help you, but my back is against the wall because I don’t get paid for two more weeks.

After failing three quizzes, my son's back is against the wall and he's got to pass all of the rest of them.