What Causes Burning Sensation In Neck And Head?

30 year old female, head and back of neck feel as if they are burning up from the inside out, causing a feeling of hot throbbing pressure inside my head. Eyes feel extremely heavy. No fever. Does not feel like a headache. Can t seem to focus on words when i m trying to speak causing me to stutter and stumble over them. This has lasted about 12hrs so far.