I went through a period of constant headaches, particularly waking up with them. I eventually went to the doctor, who did the obvious checks, including asking if I had had a recent eye test, which I had. He told me to take ibuprofen every 4 hours and in between paracetamol to stamp on it, but to no avail. In desperation I went for another eye test, only to find my eyesight had deteriorated suddenly and I needed new glasses! Expensive solution, but actually a huge relief. So do have your eyes checked. Sometimes even a small change can result in headaches. Also make sure you are drinking plenty of water, as dehydration can trigger headaches. And if you are on medication, read the blurb for side effects. Sometimes, some medications include headaches as a side effect.