Draft Picks!

how come none of the teams want to trade me draft picks?

It's just the way the CPU's trading logic works. It's a little more difficult to trade picks than it should be, but there's nothing you can really do about it. Teams aren't usually willing to give up picks too early in the season, and it's difficult to get a team that's likely going to get a top five pick to give it up, even for a really good offer.