Firstly, get rid of CleanMyMac. It's third party malware and challenges the permissions of your native applications and will cause problems. Apple recommends that you DO NOT run any anti-virus or sweeper software, because it causes underlying issues. Just uninstall it by dragging it to the trash. Even if you think it's working right now, it's eventually going to cause system slowness and issues with apps. Trust me on this.
Secondly: This is a permissions issue.
Restart your computer holding Command R
Select English as your language. Continue.
Up at the top left, choose 'Utilities' and 'Terminal'
Type 'resetpassword' with no spaces or caps
Select Macintosh HD, then your username
At the bottom of this list select 'Reset Home Folders and Permissions' (no data loss, just a permissions reset)
After it's done, re-start your computer, launch iTunes, then plug in your phone
File -- Devices --- Sync
Should be resolved
Hope this helps. Now get rid of that awful third party software.
That's not a good sign. Manually shut down your computer and boot to your desktop.
Drag all that third party software you have to your trash, it's going to ask you for your admin password, put that in and make sure you empty your trash.
Finder -- Applications -- Third Party stuff -- Trash -- Password -- Empty
You might see some popups asking why you're uninstalling. Just fill them out but get that trash emptied.
Now you need to run a software update. Apple -- Software Update -- everything in this list.
Once that's done, you may need to restart.
If you do that's fine, do this next:
Finder -- Applications -- Utilities (folder with blue tools) Disk Utility -- click Macintosh HD --
Under 'First Aid' which will be selected by default click 'Repair Disk' then 'Repair Disk Permissions'.
That third party software has messed up more than is probably good.
If this doesn't work you're headed for an archive and install. What OS are you on?