Each fall I get a lot of phone calls from worried homeowners concerned about their White Pines and other evergreens. They see pines, spruce and douglas-fir getting brown needles and are concerned the trees may be dying. Most of the time it turns out to be normal fall needle drop - my favorite diagnosis, because it’s always nice to tell people “don’t worry, your trees are fine”
Just as non evergreen trees shed their leaves, evergreen trees need to shed their leaves (needles) as well - it’s just not all at once. For most evergreens this tends to be 2-3 year old needles. It is normal for pines to drop their oldest (inner) needles at this time of year. If the browning is internal - meaning not at the tips of the branches - and the brown is uniform throughout the tree, it’s probably just normal fall needle drop.
If you are concerned, have a Certifed Arborist come by and take a look.