First, be aware that tax reciprocity applies ONLY to employee compensation (an employee receives a W-2 at the end of the year).
If your permanent home (your domicile in tax lingo) is in MD, and you are in PA temporarily to attend school, and your only income in PA is W-2 compensation, you do not have to file a PA tax return. Your income is instead totally taxable by MD.
If that's your situation, file PA Form REV-419 with your PA employer to make them aware. Here's a link to that form: http://www.revenue.pa.gov/FormsandPublications/FormsforBusinesses/Documents/Employer%20Withholding/r...
In order to receive a refund of incorrectly withheld PA taxes, you will have to file a non-resident PA tax return, showing zero PA income. Note that only incorrectly withheld PA state tax is refundable. Any local or city taxes being taken out of your pay are not refundable.
**Answers are correct to the best of my ability but do not constitute tax or legal advice.
