I've been having constant headache from past 15 days. It starts early in the morning and goes on till 7-8 pm. It generally starts with either eye pain or headache (left side and then starts paining the whole left side of the head) I got cold couple of weeks back but still coughing. I also got checked up with sinusitis thinking that could be because of my power change. Still no relief. Optometrist suggested that headache could be of sinusitis.