You cannot go scuba diving with a headache, but not for the reasons you might think!
Before starting scuba diving at all, you complete a medical questionnaire. And there are many temporary conditions with which you should not dive, such as congestion. Congestion, for example, can interfere with your ability to equalize the pressure in your ears, which can cause discomfort and pain in your ears, and which can also lead to serious ear injuries.
So, you might be thinking that I am about to include headaches among those temporary conditions with which diving is ill-advised, but I am not.
CAPTION: my headache reliever of choice while above water
Allow me to explain. I have headaches all the time. If the headache is not at the base of my neck or on the top of my head, I at least have serious, work-related eye strain. In a nutshell, some part of my head is usually hurting.
However, the pain goes away underwater. I’m not a doctor, but I would theorize that this is pressure related. If I am on the surface, I apply manual pressure to my temples, the bridge of my nose, the back of my neck, and so forth. But, while submerged, my body is subjected to greater pressures.
If pressure isn’t the reason, maybe it is the distractions of the undersea world or adrenaline or something. Whatever’s doing it, I remain pain-free throughout every dive, as well as for some time afterward.
For that matter, I am old enough to have injured quite a few body parts over the decades. Nothing hurts underwater. Well, except for the one time I got stung by something, and that only hurt a little.
So, in my unprofessional opinion, it is not possible to dive with a headache.