YOU SAID:
My bottom hurts because I worked out for a long time yesterday
INTO JAPANESE
私は昨日長い間働いたので、私の底が痛い
BACK INTO ENGLISH
My bottom hurts because I worked long yesterday
INTO JAPANESE
私は昨日長く働いたので、私の底が痛い
BACK INTO ENGLISH
My bottom hurts because I worked long yesterday
You've done this before, haven't you.