Anyone have headaches while on an aromatase inhibitor (AI)?

In researching my own issues, I found that vasoconstriction caused by an AI can cause headaches. You might check with your doctor if this could be the cause, and if there is something that might help relax the vascular system.
It seems doctors don't address the side effects that don't meet the scientifically “significant” level - that is, not enough people have them or the effects aren't severe enough. You're probably in the “not enough people have it” category.

It could be that the level of vasoconstriction is dose dependent, so if a lower dose would still protect you based on your cancer profile, then that might help. There are foods that are supposed to induce vasodilation (beets, spinach, citrus, garlic) but I don't know if you could eat enough to help. There are also supplements that increase vasodilation but you'd want to check with the doctor before taking.

I have the opposite effect on tamoxifen, because I’m old. It acts as an agonist (positive force) and causes vasodilation in the brain vascular system causing headaches. My tamoxifen dose was lowered by the oncologist and my regular doctor recommended a nasal spray that induces vasoconstriction. My headaches stopped.

Thank you triciaot for your very helpful and on-point thoughts.
I was/am between a rock and a hard place with the recommended AI's for treatment of my breast cancer. It was the only recommendation for my treatment post-BM. I have ischemic heart disease since my 50s and really shouldn't even be on the AI's because of (as you mentioned) the vasoconstrictive effects. I am at risk for a heart attack or stroke. One of my cardiologists who I hold in high regard reluctantly gave his "OK" to treat my breast cancer as recommended. I will be seeing my breast oncologist in 2 weeks and will be discussing this issue with her. Wonderful to hear your headaches stopped. The very best to you!