Are you flying through ORD or JFK? Or are these questions related to two separate itineraries?
http://www.flyertalk.com/forum/new-y...ld-i-head.html

At both JFK and ORD, AA and BA operate from separate terminals and access to their lounges is limited to flights from the same terminal. If flying F, you should probably utilize the Flagship Lounge, if you want a shower or more room then go to the H/K Admirals Club.
http://www.flyertalk.com/forum/ameri...solidated.html
http://www.flyertalk.com/forum/ameri...er-thread.html