Hi so I know this is a really old forum but just in case people are looking for answers because I was looking at this forum when I was having the exact same problem. About 3 months in of having the mirena, out of no where I started having really bad neck pain and shoulder pain and then after that just constant headaches and migraines 24/7 for 4 weeks straight. First doctor said it was tension headaches so I tried PT, chiropractor, massages and nothing helped. After the 3rd week I started to think it was the mirena iud so I got it removed. By the 4th week I had so much pressure behind my eyes I couldn't even see straight I was seeing double vision. I ended up having pseudotumor cerebri where so much spinal fluid builds up it puts pressure on your brain and optic nerves causing the headaches and blurry vision. I got a spinal tap and normal spinal fluid pressure is 10-15 and mine was 80. I got all of it removed and I felt instant relief. No more headaches no more neck pain and since I got the mirena removed it has not built back up again since! My biggest regret ever is getting the Mirena and it's frustrating that every doctor and gynecologist I've seen says they've never heard of side effects like this when clearly many people do.