My tax return was accepted but not processed yet. Do I need to register for the stimulus check?

No, you don't need to anything for your Stimulus Check since you have already filed your return.

Thanks for the reply. I also forgot to mention that I got a letter saying I need to verify for my refund March of this year. I set up an appointment for April 7 but the IRS cancelled and hasn't contacted me back yet. I'm at a lost what my options are. I saw an article that TurboTax was working with the IRS on the stimulus,I thought maybe they could help me out with getting my return fully processed.

Once the IRS has it, it is out of our hands, but I've often had success with the local office.

To find a Local Office:     Local IRS Offices