I assume you mean what challenges after they gained independence. They had many internal conflicts. This included fighting about religion. There were also natural disasters. There was the problem of transitioning directly from a dictatorship to a democracy.
No taxation without representation" is a slogan originating during the 1700s that summarized a primary grievance of the American colonists in the Thirteen Colonies, which was one of the major causes of the American Revolution
ones in the eyewitnesses point of view and the encyclopedia is more detailed
Those who opposed giving the federal government more power than the states were known as the "Anti-Federalists", since they did not want to ratify the Constitution, which would have done this.
