I feel like it depends on what the headache is caused by (stress, hunger, environment, etc.) but try eating something or take a nap or relaxing in a quiet environment. Nothing is going to work super fast and even pills take a couple hours
There are several things you can do for a head ache:
1. Try taking a nap - in a cool dark room. (Stay out of the bright sun light.)
2. Use a cold compress. If you feel your head throbbing and or your neck and shoulders aching - try using an muscle ointment (I know you said no medicine) or something to relieve the stress. If you do not have any muscle ointments - try using some hand cream and massage your neck and shoulders.
3. I find eating something - not necessarily a big meal - if you are not allergic to peanuts - try a couple of spoonful of peanut butter - I'm not sure if this helps me because there is something in peanuts or it is just a comfort food for me.
4. If you are feeling stressed try to do something that gets your mind off of your problems.