My nipples hurt when II touch them can this be a sign of pregnancy? And when does implantation ouccr?

Possible. The Progesterone level starts to increase after ovulation and continues to rise as a result of conception. Progesterone can make the nipples very sensitive - this sensitivity is ususally noticeable just before a woman's period is due. If she conceives, the sensitivity can worsen during the first weeks of pregnancy.
Can, but. Breast tenderness can be a sign of pregnancy, or that your cycle is about to start. Implantation occurs approximately 6-10 days after ovulation.