No, you do not need to file a NYS return (unless you have other, non-pension income from NY).
Your NYS pension is only exempt from NY tax (helpful if you were still a NY resident), but it is not exempt from PA tax.
Effective for retirement income received after December 31, 1995, federal law prohibits any state from taxing certain retirement income (mainly pension income) unless you are resident of, or domiciled in, that state. For example, if you receive a pension from your former California employer and you now reside in New Mexico, California may not tax your retirement income. Because you are now a New Mexico resident, your retirement income is taxable in New Mexico.