I had episodic asthma, I am 63 years old. I had run the marathon a few years ago but recently I was finding running or playing tennis difficult. I started on combination inhalers and it didn’t much improve the situation. So about 3 months ago my GP prescribed me Montelukast. I have been through lot of stress over the last year or so. I am on antidepressant and I do feel a bit low from time to time. Last 2 and half month I noticed that I had serious pain on the left side of the back of my head. I have been using computer to do my work a lot of times. So I put this down to the computer use. But the pain continued unabated and spread along the left side of the head including the let eye. It became a constant feature. It may be a deep pain behind the left eye along the left eye brow, left side of the forehead and burning sensation under the hair on the left side of the head. I had to take regular paracetamol and diclofenac to get control. I thought it is the computer smart phone and anxiety. Over the last few days I started thinking this not me, how can computer use cause so much pain and paraesthesia and I am anxious but the anxiety is controlled and the physical symptoms are out of proportion of the psychological stress. I saw the side effects of Montelukast and stopped the tablet last night. A slight improvement pain and burning not so intense. Any advise from anyone?