How Can Migraines With Visual Disturbances, Face And Head Pressure Be Treated?

I am suffering from migraines every three to four days with visual disturbances . I am 57 years old. Had an induced menopause after breast cancer . Was given tamoxifen for 5years. Have not taken any medication for last 2 years and am all clear from cancer. When I have the migraines I have visual disturbances over one eye then pressure in face and at front of head. My GO is talking about giving me prophylactic medication. But I do not have severe pain with the migraines , more like pressure. I have been taking migraines which seems to work but I am concerned about the frequency of the migraines and now I am experiencing stomach spasms which I think may b related to the frequency of painkillers I am taking. Can u suggest any alternatives of treatments or reasons for the sudden frequency of the migraines?