[stjarnljuset]

Wow, I've experienced getting headaches every time that I've gotten a new pair of glasses. I never thought it would be because the pupillary distance was off. I just thought I had to adjust to the new prescription. But half of them were from a brick and mortar store so I'd expect them to get the pupillary distance right.

[jtolj]

I think that a big change in prescriptions can cause it temporarily as well, but definitely have them re-check the prescription/PD. A surprising number of mistakes are made.

Also if you notice that your eyes aren't centered vertically in the frames, that can mean the optical center is off which can lead to headaches.