RonFrank
Contributor
Ask any doctor, including headache specialists, and they'll tell you how hard headaches are to diagnose. And that's after taking a detailed medical history.
The op did not post a history of headaches, so we can ASSUME that the headaches are diving related. In that case, they are not all that impossible to diagnose as there are just a few root causes.
If the OP has a history of headaches, they should say so, and we can all agree that they may need to see a doctor. If not, skip the skip breathing, and/or loosen the mask, and see if either helps.