[ameliorate]

Have you tried massaging your head with your fingertips? Often you will find a sore/tender spot and this locates where the headache can spring from. Gentle, circular movements (with fingertips) can make the difference! Initially it might feel painful but, working very lightly, the pain often dissipates. I share this from personal experience e.g. when I used to get the onset of sinusitis (I'd massage the tender spots either side at the top of my nose.) It's acupressure by any other name.

Constant headaches may well need looking at though, i.e to be diagnosed since they can be an indicator of something else, unless you know the cause e.g. stress related. If it's this then dealing with the cause at onset would be advantageous rather than letting it develop into a headache later.