A Member of Congress is either a Congressman or a Congresswoman. Members of Congress have been elected to serve in the American Congress. Someone who sits in the House of Representatives is known as a Representative while someone who sits in the Senate is called a Senator.
Congress is largely made up of people who want to be Congresspersons, which is the start of the problem. The other major issue is that nearly half of Congress consists of conservative Republicans, which is sort of like having the political fate of one's country controlled by a committee in which half the members are in the bottom tiers of intelligence and decency. Well, it's exactly like that, actually.