i just woke up half hour ago with an intense burning feeling in my face and entire body .it was like my entire body was on fire .it seemed to spread quickly from face and involved both arms and legs and trunk too .
im 42 years old take medicines for hypertension and dyslipidaemia including niaspan/niacin but i havent taken any new medicines .
the feeling has subsided now but it lasted prettty much 15-20 minutes .my blood pressure at the time was 100/70
never had anything like this before .i was sound asleep and this thing actually woke me up at 3.30 am

i thought of a TIA like a brainstemTIA but i would have expected symptom to be unilateral and perhaps some other symptom as well

any thoughts ?

Niacin will do that --it is called the niacin flush.

If you are allowed aspirin, take one regular strength an hour before the niacin, and it may block the flush.

Some get the flush every time, some don't.