Is this too many items on a 20 AMP Breaker?
Whether or not that's too much depends on what is plugged into the outlets, how often each item is used, and how many items are used together.

That seems like far too many things on one breaker to me. If I was wiring that, I would not have done it that way. Now that it's already like that, fixing it is most likely a big chore. If, and that's a big, unlikely if, you're lucky, you may have more than one wire run coming into the electrical panel to that breaker. In that case, one or more of the runs could be moved to a new breaker (assuming there's room in the panel, and I find it hard to believe there isn't). Working in an electrical panel is dangerous and must be done by an individual that understands what they're doing, be it you or an electrician. Please be careful.

If you're not lucky, there will be one main run coming off of the breaker, and it's split somewhere in an electrical box in your home. If you're so motivated, you can chase this down and find the splits. Then you could fish new wire runs from a new breaker to one of the splits. 

Good luck with whichever method you chose.