Your nocks may be too tight, you may have a rough spot in a nock or two, or you may have gotten some bad serving material. I prefer #62 braid or Halo from BCY. #62 comes in 3 sizes, Halo in two, so you can use the one that best fits your nocks. Both are very durable, Halo is super slick, and both are fairly expensive. If you need more info. on them, just holler.

Chad