What were the causes of unrest in the American backcountry in the mid-eighteenth century?

The major cause of unrest in the backcountry in this time
period was discontent with the performance of the colonial governments.  The colonial
governments were run by elites from the coasts and the backcountry people felt that
these elites were insenstive to their needs.

Most
importantly, the backcountry people wanted to be protected.  They were living on the
frontier where they faced threats from Indians and outlaws.  They wanted the government
to do more to protect them.  When this did not happen, rebellions like that of the
Paxton Boys in Pennsylvania took place.

In addition,
backcountry people sometimes felt cheated and abused by the coastal elites.  They felt
that the government was acting in ways that helped the rich at the expense of the
backcountry farmers.  This sort of complaint led, for example, to the "Regulator"
movement in North Carolina.