I often take painkillers (acetaminophen aka paracetamol), but I’ve noticed that it’s much more effective if I take them TOGETHER with my ADHD medication (ritalin aka methylphenidate) + my morning coffee. If I don’t take them AT the same time, the painkiller is far less effective.
I do not exceed the maximum dosage of painkiller (1gram per intake, mornings), but alone this would barely suffice to kill my morning headache.
My hypothesis is that since the LIVER has to convert all three, I am effectively overdosing on either substance (painkiller or ADHD meds), and damaging my liver in the process.
If you have the option, I would suggest going to a Dr before assuming anything is the only plausible explanation.
Personally, I found out about my neck / posture issues (even though outwardly I have decent looking posture so I never assumed it would be that), got some excercises from a physio and a completely different pillow, and that combo drastically reduced my headaches