“Chronic headaches ”

For the last 2-3 years, I have had fairly mild headaches about 5-6 days a month. The pain varies but is never severe. I feel like it may be sinus related. The pain is in my forehead, eyebrow area, and at the base of my head/ top of neck, sometimes a little in the ears and often seems to correspond with nasal congestion. Sometimes it lasts a few hours, sometimes all day. It occurs all year, not just allergy season (I have a history of seasonal allergies). Besides the nasal congestion, no runny nose or sneezing like I’ve had in the past. I do sometimes feel drainage in my throat particularly when tilting my head back. For the last month I have tried taking Zyrtec and it hasn’t really changed anything. Just recently, some mold was discovered at my work place. I have not been able to figure out any pattern in the timing of my headaches. But I’m wondering if mold exposure could be the cause. Is there any test that could be done to check for sensitivity to mold so I could determine if that is the cause of my headaches? Obviously I can’t just stop going to work. Or any other ideas for what could be causing my headaches? Thank you.