I just got over a case of food poisoning about 4 days ago and during/since that time have been experiencing one extremely bad headache. I have no history of headaches or migraines, no symptoms of glaucoma or any other such disorders, and no fungus or anything like that. The day after I was starting to get over the food poisoning I felt like I had an extremely stiff neck , and since then it has been on and off, anywhere from feeling normal to becoming increasingly more stiff throughout the day. Same goes for the headache, during the day it is a slight pain, with it increasing as it goes on throughout the day. Again, no prior headaches or chronic migraine pain, this is only during and after the food poisoning incident. Is this normal?