It does sound like anxiety of some sort: Chest Pain and Vomiting: 17 Causes, Photos, and Treatments

Is it during the time before/during her period or anything? That's the first thing I thought of, that it might be hormone-related. I would go to a good gynecologist and get a work up through her/him; get blood work done, etc. Then I'd do a bit of a symptom journal and look at everything -- does she have a monthly report due at work or anything like that? Special meetings? Reviews? Group work (and has trouble with somebody in the group)?