Why have I got a headache today?

[Biggsy]

My day today is not much different from headache-free yesterday and the day before, in terms of food, drink, medication, sleep and activity.  What causes are there for headaches that happen for no apparent reason?

(I haven't touched a drop of alcohol for a long time, and I don't do illegal drugs.  The the prescription drugs I'm on generally result in fewer rather than more headaches, so I don't believe it's that).

[Eccentrica Gallumbits]

Dehydration? Stress? Someone stuck an axe in your head and you didn't notice?

[Biggsy]

Didn't notice an axe or more stress or less hydration than usual.

[hellymedic]

Try drinking a pint of squash. If your headache clears, it's due to dehydration; if not, no harm done.

[Cudzoziemiec]

Air pressure?

[Jessy12]

 You need more rest,good luck with you

[Biggsy]

I think you're right, Jess, thanks.

I'm now suspecting it's just an accumulation of things, rather than there being anything particularly different on the days I get headaches.

[TheLurker]

It's Monday.

[Ashaman42]

Badgers jumping on your head whilst you're asleep?