Work in Philly live in jersey

Please someone smarter than me help me. I live in nj but work in philly. 
On my pay stubs i pay Philadelphia income tax and nj income tax. Significantly more to Philly. 
On my w2, nj is in box 15. 

Finally caved to get a live agent that totally didn’t care or know any better than me. Total waste of time and money. Tried telling me i owe nj 1400 dollars. in addition to over 300 to file for both nj and pa. On that fact alone, i think she was trying to scam me. I don’t think i need to file both. Can someone with a brainstem actually help me. And maybe dumb it down for me so i can understand how to just do this myself. Im single with like no assets.