If you had MD withholding on your pay checks, then you should get a MD refund. But as a PA resident, all income is taxable by PA so you owe taxes on your MD income. PA and MD have a reciprocal agreement that MD will not tax PA resident/s wages.
1. Read this, and get that withholding stopped ASAP:
http://taxes.marylandtaxes.com/Individual_Taxes/Individual_Tax_Types/Income_Tax/Filing_Information/D...
Some MD employers will withhold PA taxes, just ask.
2. Complete federal income tax return.
3. Prepare a MD nonresident return, see MD instructions in the above link. If your only MD income was from wages, you should get a refund of all taxes withheld.
4. Prepare a PA resident return, declaring all income, regardless of where earned. Unless you made PA estimated payments, you likely will owe quite a bit.
5. If your employer won't withhold PA taxes (he's not required to do so), consider doing PA estimated taxes.
