I had my second vaccine 3 weeks ago. For the past 10 days I've had a headache that will just not go away. It eases with tablets but doesn't go and as soon as the tablets wear off it's back. Today I read a thing that said if a headache between 4 days and 4 weeks of having jab that doesn't go away youbshould phone 111. But if something bad was going to happen it would have by now wouldn't it? Just want the headache to go away.