Always suffering mild headache and sometimes severe. i feel the headache is mainly on the right side. what could this possibly be.please advice.

Keep a headache log: There are many types of headaches and many reasons for each type. It would be helpful for you to keep a headache calendar by noting down the frequency, duration, location, characteristics, and intensity of your headaches, along with associated symptoms. Take the headache calendar with you to your primary care physician for dicussion. http://www.nlm.nih.gov/medlineplus/headache.html