YOU SAID:

i walked to the store about three days ago

INTO JAPANESE

私は3日ほど前に店に歩いた

BACK INTO ENGLISH

I walked to the store about three days ago

INTO JAPANESE

3日ほど前に歩いて来店した。

BACK INTO ENGLISH

I came to the store on foot about 3 days ago.

INTO JAPANESE

3日ほど前に徒歩で来店した。

BACK INTO ENGLISH

I came to the store on foot about 3 days ago.