personal business vs personal matters

personal business and personal matters both are nouns.

Word	Noun	Adjective	Verb	Adverb
personal business	Yes	No	No	No
personal matters	Yes	No	No	No

As nouns, personal business and personal matters are synonyms defined as:

Other synonyms of personal business include affairs.

personal business (noun)	personal matters (noun)
matters of personal concern	matters of personal concern