1) Nav tab only can display so many systems. If your jump range is large enough, it won't display everything you can reach.
2) Check the gal map. There is a cargo slider that allows you to plot a route, taking into account the cargo, even before you actually have the cargo in your hold. Maybe you have this slider set to max.
3) As for the same guy chasing you - do you have a bounty somewhere? Could it be a bounty hunter? Or he could "belong" to some mission you have active. You can get rid of a bounty if you buy a Sidey and ask some commander to KWS you and kill you. If he belongs to the mission, he's there to stay until you kill him or finish the mission.