I am flying on American. My flight will arrive at terminal C with a connecting flight (American) leaving from terminal B. Do I need to go through security again to go between the 2 terminals? It looks like this on the airport map. Thank you.

There is a shuttle that runs between the two piers every 5 minutes. Otherwise, as of this post you would have leave security. Hopefully, by 2020, the National Hall, as they call, it, will be behind security, and TSA will be pushed back and below the metro. This will allow walking transfer for American Airlines customers between what will be 3 piers, B, C, and the New North Concourse.

B and C are in the same place

Yes the shuttle is close by

American runs a bus between B and C so you don't have to clear security twice. The signs are easy to miss though.