The ticking sound you hear does sound like it could be a hard drive that is recalibrating after an error, but there is also a fan inside that can cause ticking sounds. Keep in mind that it is normal for hard drives to make some noise when they access data, but if the noise is excessive then that could be indicative of a problem. The most important thing any user should do is make sure they keep a backup of their data. It's a lot easier to recover from a bad har drive when you have a backup.
If you haven't already done so, make a backup while you can. Trust me, I lost my hard drive once, and it contained very important family photos. I now keep a current backup at all time.Once you have a backup then launch the Disk Utility application located in the Applications/Utilities folder and run the First Aid option to see if it identifies any errors. For a more detailed look at the hard drive's error logging you can download an app like Smart Utility from Volitans Software which will pull the detailed SMART logs and let you know whether there are errors that you should be concerned with. You can run it in the demo mode for a limited amount of time.
https://www.volitans-software.com/apps/smart-utility/
