A man shot himself in the shoulder Sunday afternoon in the Logan Square neighborhood on the Northwest Side, according to Chicago police.

The 20-year-old suffered the self-inflicted gunshot wound to the shoulder about 12:30 p.m. during an argument with his ex-girlfriend in the 2500 block of North Spaulding Avenue, police said.

He was taken to Mount Sinai Hospital, police said.

It was not yet known if the shooting was an accident.

Area Central detectives were investigating.