If you are a non-resident of PA and never physically work in PA, then you are not subject to PA income tax. Talk to your company's HR or payroll department and inform them that you are not subject to PA state tax withholding. As Hal_Al said, next year you'll have to file a 2016 non-resident PA return to get a refund of the PA taxes they've already incorrectly withheld.
"When nonresidents perform services partly within and partly outside the commonwealth, only compensation for
services performed within the commonwealth is subject to Pennsylvania withholding." (from page 9, <a rel="nofollow" target="_blank" href="
http://www.revenue.pa.gov/FormsandPublications/FormsforBusinesses/Documents/Employer%20Withholding/r...>)
BUT, see SweetieJean's and afc42's comments above if you are a telecommuter. A telecommuter is one who does not commute to a central place of work, but instead works via the internet from home or some other alternate location of their choosing.
**Answers are correct to the best of my ability but do not constitute tax or legal advice.
