I ended up with a headache behind my right eye, which I'm pretty sure basically all headaches behind my right eye are caused by tension in my neck/shoulders, at work today after I heard some rather...idk...tense? News about a customer that's been causing trouble in our store for the past week. I haven't had to deal with them myself, but the tension from my coworkers who have dealt with him probably got to me as the customer...is a piece of work. Throwing tantrums, swearing, throwing items around the store. Yeesh. I'm glad I haven't had to deal with them. 
In any case.
The headache behind my right eye lasted for basically all of work...and then it ended up switching to behind my left eye towards the end of work as I went to run a few errands after my shift ended. It vanished a lot quicker than the one behind the right eye did, mostly because I got some more food in me and some heat on my shoulders.