The feeling of pain for being at work, or pain caused from work which includes and not limited to; headache, annoyance, bane, distress, frustration, hassle, inconvenience, irritation, pain in the neck, stress, worry.
Workache can be a long-term sickness, treatable only by time off work, preferably on a relaxing long holiday.
Work Colleague - what's up? you don't look well
You - suffering a bit of workache
You - it's been a long day, got a bit of a workache now