Headache on top of the head. Anxious!

Since last 6 months, I've been getting headache on my top right side of the head. Last month I went to a doctor, he diagnosed it as a form of migraine. He prescribed me medicines (Ciplar LA-40 & Dulane 20mg) and to certain extent it helped. Gradually, after 2 months I stopped the medication. Till that time the pain was not entirely gone, but the frequency reduced. Since last week, I'm again having headache for almost all the time. It is always the same spot. On the top right side of the head (please note, not forehead). I'm very very worried that this is not a tumour or something and I'm getting anxious regarding this. I really don't know how to explain the pain. It is on one side, kind of throbbing, but persistent. I can feel it all the time. During coughing, it aggravates. I'm thinking of getting an MRI scan. Please guide.