I had headaches frequently pre-mirena, but never really stopped my life. I also had dizziness issues, which my neuro tells me is part of the migraines for me.
But I know the hormones in mirena didnt help mine at all. I have had some form of a headache almost everyday for the past year or so. I did managed to get a break in them recently a bit. Thankfully, mine are not 'typical' lay in bed and cant do anything migraines, but rather horrible annoyances that affect my driving and balance and patience.. but I do know it was coorilated to getting the mirena. The frequency and intensity did change.