I think with something this specific and especially if it is a new symptom, or recent onset, that you need to have it checked. If you don't have a headache specialist or know of one, your family doctor would be a good place to start. Imaging is almost always called for to rule out everything from kitchen sink to bubonic plague, but it is a place to start.
With something that is so rhythmic it could be hormonal; a tubal ligation does not stop ovarian function and that has to be considered. It can also be tied to stress factors at work, home, and as odd as it may sound, lunar cycles as well; clenching teeth while sleeping causes a lot of headaches. So there's much that this could be.
Depending on the type of pain med and the frequency you take it; it is possible that you could go into a rebound situation; it doesn't sound like that is the case..yet..but you don't want to go there.
I would call my family doctor (my FD is incredible and I trust him completely...not everyone has that), but before someone just throws hormonal in your face, get it checked. You didn't state your age, but if they think it is hormonal, request blood work to see what your estrogen/progesterone levels are and go from there.