I've had bad headaches since before I was 10 years old. I remember some car trips from back then, when I'd have a shocking headache and just deal with it, because it wasn't anything new at that stage. They got more frequent over the years until when I was 14-17 they were almost daily. Certainly every day in my final year at school (year 12/form 6) I'd wake up, take two paracetamol (Tylenol) and wait 10 minutes until that kicked in before getting out of bed. Bad days would have me take another couple of doses throughout the day. I occasionally went over the maximum of 8 tablets a day when the pain was that bad. At some point I discovered Panadiene (paracetamol + codeine phosphate). That helped immensely with the stronger headaches.
Aspirin gives me shocking headaches. Guess that's some kind of intolerance. Kept me away from trying ibuprofen for years.
When I was about 25, a dentist asked me whether I grind or clench my teeth at night. I said yes, I do. So I was diagnosed with bruxism and given a splint. This was miraculous and cut the daily headaches down to 3-4 a week.
I only take pain relief once my headaches reach a 4-5/10. Everything else, I just sort of compartmentalise away, and soldier on. I'm so used to living with a background of pain, that sometimes when I realise it's not there, I get quite a surprise.
These days I take 2 x ibuprofen (200mg each) and 2 x paracetamol (500mg each) for almost any headache. If it's particularly bad, I'll take the above but with one combined with codeine phosphate (11mg each) and if it's excruciating I'll take both of the above combined to give a total of 44mg codiene. This is not always enough, but it's the extent of the drugs available to me.
My headaches mostly match the typical description of tension headaches. Pounding, crushing pain, sore behind the eyes etc. If pain relief works, they often don't come back that day. If it only reduces them to a dull ache, then as soon as it wears off then there's a good chance the pain will be back with a vengeance. Sometimes they last for 3 days like this. If they're intense enough (9-10/10) then I'm useless. Unable to do anything to look after myself, or anyone else. Pain relief (even with codeine) only ever knocks the headache down about 5 notches, so a 5/10 might be "cured", but 9-10/10 still hurts and affects me.
Recently the headache frequency has been creeping up again. In 2011 I had one period where for 21 days straight I had at least one headache bad enough to require pain killers. If I got my dose right, and early enough, then usually that'd be that, for the day; but for at least 7 of those days it was a multi-dose day.
I get migraines too. They usually start at 11/10 on the scale, and really wipe me out for 3 days (24-36 hours of pain, then the same again in feeling scattered and fuzzy). I don't get auras, but I distinguish them from my tension headaches by how they feel, and how I feel, especially after the pain has gone. Fortunately these are about 3-4 times a year. OTC meds don't work on my migraines at all. So I drink blue gatorade/powerade, go to bed and endure. Fortunately, while I'm usually extremely good with judging the passage of time normally, I don't have any ability in this regard at all with a migraine and whole hours can fly by without me really noticing.
Headache triggers seem to include: not enough sleep, weather changes and moving between air conditioning/heating and not, overheating, crying, pounding exercise, exhaustion, stress. The only migraine trigger I'm aware of is substituting caffeine for sleep for more than 3 days in a row (which seems to be having any caffeine any time of day for more than three days in a row). I get more migraines than that accounts for.