Why would my NC state tax return be over $4000 when I've only lived in the state 4 months and worked a $16 an hour job that did not contribute near that much taxes?

we can't see your return or the w-2.  check your entries especially the decimal points. 

...Also  (if you moved to NC from another state):

Go thru the NC Part Year Resident interview again.  You may have mis-assigned some of your prior yearly income as being NC-taxable.

As a note...NC does calculate a tax based on ALL your income for the year, but then ratio's it down based on what portion you indicate you earned-or-received after you became a resident.