All conifers shed their needles, including eastern white pine (Pinus strobus). Needles are shed every year, however, some years the needle shedding is much more pronounced and noticeable -- this is completely natural, unless of course all your tree's needles fall of at once leaving the tree completely bare!
The white pine's needles will not kill the periwinkle; however, conifer needles can increase the acidity of the soil.