Rapid fire cursor and ping sound

I have iMac Sierra 10.12.6 Several times now my cursor starts flashing rapidly and I can't click on anything. I can move cursor around but clicking on anything results in a quick flash of the info. At the same time the computer makes a constant rapid pinging sound. I have to shut down computer and start up again to get it to stop, but after a while it will start pinging and flashing the cursor. This happens even if I'm not using the computer. I have wireless keyboard and trackpad. How can I fix??