I had an appendix removal and one of the dissolvable stitches hasn't dissolved. Its been 2 years. A little bit is sticking out and is itchy sometimes?

See surgeon. See your surgeon. That is not normal. That wasn't a dissolvable stitch then or it's some fiber development in the tissue post-op.
Have it removed. Not to worry. The wound is well healed. If it bothers you, ask the surgeon to remove it.