What Causes Headache With Heaviness Feeling And Blurred Vision?

Hi, I am a woman of 26 yrs old. I am suffering from a problem of headache which lasts for 2 to 3 days in a month. This is the case for the last 4 years. The pain is uniform throughout the head and the feeling of heaviness. For the last one year, I was using Evion- 400 for temporary relief whenever the pain was severe. But off-late the duration of pain has increased and I am experiencing a blurred vision during the headache. Just for your information, I have hypothyroidism post pregnancy and I am on medication for the same which is under control. My height is 160 cms and weight is 70 kgs.