First of all, I am sorry to hear about your flight diversion.
According to this policy, published on AA.com:
http://www.aa.com/i18n/agency/Bookin...tkt_policy.jsp
AA to/from AA or a oneworldŽ Carrier
If a customer is holding separate tickets on AA or another oneworld carrier, customers holding separate tickets where travel is on oneworld airlines should be treated as through ticketed passengers. In the event of a disruption on the originating ticket, the carrier responsible for the disruption will be required to reroute the customer to their final destination. The ticket stock of the second ticket must be of a oneworld carrier, eligible under the Endorsement Waiver Agreement. You may contact AA Reservations 1-800-433-7300 (U.S. and Canada) or outside the U.S. and Canada, reference Worldwide Reservations Numbers for additional information if the separate ticket is for travel on a oneworld carrier.
Even though you had a separate reservation, seems like you should have been accommodated by AA rebooking you to HKG, either by way of the direct ORD-HKG flight (which, if you landed in ORD before 1 PM, you could have made it same-day), or the next day.
If I were you, I would call AA again and cite the policy, to see if they can accommodate you. Also, you may want to call your CX reservation hotline to see if they can make a good-will flight change for you to switch to the next day's PVG-HKG flight.