Then if you have access to the sql server, run this query to see if your user has specified tiles already.
select userid, username, usersettingsid, UserDashboardApplications
from CMS_UserSettings
left outer join cms_user on userid = usersettingsuserid
If the UserDashboarApplications field is not empty, run this query to clear it out.
update cms_usersettings
set UserDashboardApplications = ''
where UserSettingsID = 0 and usersettingsuserid = 0
Of course replace the 0 (zeros) with your correct IDs. Then clear the cache in Kentico and restart the application. Log out of Kentico and log back in and see if this resolves the issue.
What happens is if you're assigned to a role, it automatically uses the predefined dashboard items. If you've customized the dashboard for your user then it stores that in the mentioned field above and that takes priority over the predefined items.