What Causes Dull Headache On One Side Of The Head?

hi, iv ben getting these medium pressured headaches for the past 3 weeks. i take medication for bipolar and have just taken a blood test. some levels were high. I'v gone to an eye doctor ;i got glasses but still the headache is there. i dont get these headaches at spicific times. the headache is located only on the right side of my head. i am 20 yrs old and overweight. should i be concerned? please help thank you.