Actor Daniel Radcliffe was forced to cancel his commitments and seek medical attention after his headaches became extreme. The 22-year-old was diagnosed suffering from a condition known as cluster headaches which causes intense pain on one side of the head and is experienced by just one per cent of the population, reports dailystar.co.uk. “I was in the middle of these weird things called cluster headaches. It’s very rare evidently, but it’s exceptionally painful. I was taking 12 strong painkillers a day and going, ‘Why do I still have a headache?’,” he said.