My suggestion would be to go to your local branch and see about a consolidation loan to pay out the Chase debt. The interest rate will be much lower, you will have a set payment on set dates which I imagine would be automatically debited from your account.
Installment loans effect your credit score differently than revolving credit. It is generally considered to be better to owe on a loan vs a credit card, because with installment loans you have a definitive end date, and set amortization. With revolving credit you can re use the credit and potentially never pay it off in full.
You will probably save a couple of hundered dollars on the monthly payment as well. If you are paying 3% of $20000., that's $600 per month. The same amount on a loan would probably be closer to $400 per month. If you can pay the additional payment easily, then I would continue to do that to reduce the payment even faster (but set the required payment lower, so if something comes up (unexpected expenses, emergency, etc) you will only be required to pay the lower payment.)