The shooting happened on Sunday night near the AMC theater on Illinois Street.
The 46-year-old woman, who was visiting the city from Connecticut, had just finished dinner with her 11-year-old son when a stray bullet hit her arm near Illinois and Columbus in the Streeterville neighborhood just after 8 p.m.
The incident has escalated concerns about large teen gatherings happening outside a nearby AMC movie theater.
Ald. Brian Hopkins said a large group of teenagers was being kicked out of the AMC on Illinois Street on Sunday evening when one pulled a gun from his backpack and fired five to six rounds of bullets.
According to a police report obtained by the ABC7 I-Team, a woman and her son were waiting on a light change when she was shot.
Chicago police said Thursday that four suspects wanted in connection to the shooting are believed to be under 20 years old.
While there is currently a 10 p.m. curfew in Streeterville for those 18 and under, the incident happened around 8 p.m. over the weekend.
INTERACTIVE SAFETY TRACKER Track crime and safety in your neighborhood