You've had a lot of possible options to consider by now, so hopefully one of two of them will work and you'll find out what has been triggering them. I think you're right that stuffing yourself with painkillers isn't getting to the root of the problem and if it is tension which is triggering the headaches you might find that some intensive sessions of neck and upper shoulder muscle massage might help. Not so easy to do yourself, but if you have somebody who can do this for you on a regular basis it might give you some relief. Also a good self-help procedure is is regular shoulder-shrugging and circling exercises which do help to reduce muscle tension in that part of the body. if you can do them several times a day, especially if you sit staring at a computer in a fixed position, this will hopefully help.