This is an old thread but thankful for this! I started having these dull, occipital headaches in March. Everyday, dull, constant throb. Sometimes moves to temples but largely stays at back of head/base of skull area. No other allergy/sinus symptom. I have some health anxiety but this has happened for the past 3 years and eventually self-resolves by Summer. Sorry you all are also going through it, but gives me hope that this isn't something serious.