Pine tree blight
Here is a link to a Penn State fact sheet on diseases of pine. If you look at the symptoms and find a match for your pine, I would take a sample in to your local Penn State extension and have them send it to the plant clinic for verification.
The second thing to look for is insect activity. Pine tree woolly adelgid feeds on the sap at the base of the needles and desiccates them. Right now the adelgid is out of its woolly coat, so you will need magnification to see the insect. It attaches itself to the base of the needle, so that is where you look. If you suspect aphids, scale, or adelgid, take a sample to be tested by Penn State.
Finally, check for borers and sap sucker damage. Sapsuckers drill into pines to get at the sap.and make rings of holes up high on the trunk. Borers also make holes and usually leave a trail of frass (sawdust and insect excrement).
You can also call a licensed arborist to diagnose your problem. You can find one nearby on the website of the International Society of Arboriculture.