If you always have a headache, something is obviously wrong as you're well aware. There are three main causes that will make you always have a headache if they are not addressed properly. There are numerous causes that you need to consider, if the 3 listed causes below do not resonate with you then you may want to look deeper into various medical conditions & nutritional deficiencies that may be causing your headache problems.
Everyone is exposed to stress everyday; it is not in the stress that you are exposed to but instead in how you handle the stress. If you do not live a well balanced life that allows time for exercise and wind down time than you are likely to always have a headache. Stress causes the muscles in your neck to tense which causes a headache.
Even if you feel like you are drinking enough fluids you may not be, your headaches may be stemming from not drinking enough water. A good idea to see if you are dehydrated by drinking plenty of water once the headache starts, if the symptoms are relieved from drinking water than you may be dehydrated.
Your diet may not contain the nutrients that you need or you may have a food allergy or sensitivity that you are not aware of. An unbalanced diet or a diet that contains too many sugars may be the cause of your always have a headache state.
If you always have a headache you should search for the true cause, otherwise you may have to continue to suffer through band-aid solutions with no true relief.