Part of the issue here is going to be whether you were considered to be a PA resident during that 1.5 to 2 years.
1) IF you moved to PA, with the intention of being a PA resident in a full-time position there (and only later decided, or were forced to move back to NC), then you should have filed a) part-year NC, and part-year PA tax returns for 2013, b) Full-year resident PA tax return for 2014 (and no non-resident NC tax return for 2014 unless you had a specific source of NC income....like from a business in NC, or a rental property or farm in NC)...... and then c) then the 2015 tax filing depends on when if you moved back to NC in 2015, and had a job in NC during 2015.
2) if you moved to PA in 2013 to the job there, and the job was meant to be temporary, then residency gets touchy. PA may consider you a full-year resident for all for 2014, and part-year for 2013 and maybe 2015...all because you were living/working there for more than 185 days starting in 2013. Definitely you became a PA resident if you got a PA Driver's Lisc, and registered to vote...but if you didn't, then PA may still decide you were a PA resident for that time from Move-in to Move-out. So that can get problematic to justify. Certainly, NC may have some questions about your not filing for NC full-year all that time, especially if you didn't file part year for 2013 (which would show them you moved out-of-state). But weeding all that out could take a local tax professional to deal with NC directly about your situation if NC is writing letters to you asking questions about filing those years.
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And...just in case this special applies to applies to you
3) IF you went to PA as a college student and worked there while a student, were under age 24, and were a dependent of your parents. Then yeah, #1 and #2 above are thrown out. NC gets to claim you as a resident for all of 2013, 2014 and 2015, and expects an NC-Resident tax return for all those years. Dependent college students remain residents of their parent's state no matter where the college is. But you would get to take a credit on your NC tax return, for taxes paid to PA on the PA non-resident tax return that you filed for those years (or should-have filed ).
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So a lot of details ... and you may still need a professional tax person (not a seasonal storefront operation) to deal with NC if NC is asking questions, and talking to them on the phone is not sorting things out.
____________*Answers are correct to the best of my knowledge when posted, but should not be considered to be legal or official tax advice.*
