YOU SAID:

The couch is too low and does not support my back.

INTO JAPANESE

ソファは低すぎて私の背中を支えていません。

BACK INTO ENGLISH

The sofa is too low to support my back.

INTO JAPANESE

ソファは私の背中を支えるには低すぎる。

BACK INTO ENGLISH

The sofa is too low to support my back.