I get those all the time and they last all day for me. Aspirin doesn't work (most of the time) and I hate it. I usually lay my head down on one side while putting a pillow or just pressure on the side that is facing upwards. After a while, switch sides doing the same thing. I do this a few times (mainly with my eyes closed) and most of the time it works. Also, falling asleep while doing this can help too.