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, joint pain, 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!