If you have just a slight headache that comes and goes and you are able to still concentrate without any issues then it's okay to drive with a headache.
Even people that get frequent migraines can still safely drive as long as they are able to concentrate.
But if the headaches or migraines get too severe then you shouldn't drive until the headache goes away.
If you have a headache try taking some aspirin or other headache pain reliever medicine to help get rid of the headache.
I drive a lot even when I have a headache because I have to still get to work at the office and I've never had any issues with concentration.
However if my headache was too severe where I couldn't concentrate I would not drive that day and stay home.
If you have constant headaches you should get checked out to make sure it's nothing serious although most headaches are not serious or caused by anything serious it's not bad to get checked out.