YOU SAID:

the Knife in the back hurts.

INTO JAPANESE

背中のナイフが痛い。

BACK INTO ENGLISH

My back knife hurts.

INTO JAPANESE

私の後ろのナイフは痛い。

BACK INTO ENGLISH

The knife behind me hurts.

INTO JAPANESE

私の後ろのナイフは痛い。

BACK INTO ENGLISH

The knife behind me hurts.