Pain in throat. A tumor? mri needed?

I was at yoga class and after the free workouts just before starting the yoga asana I had this sudden pain in my neck. It felt exactly like a painful muscle pull. My yoga sir quickly gave me an oil massage and the pain relived to a great extent. However, for hours , the pain in my throat persisted and it would pain a lot when I would swallow. I visited a doctor in the same evening . he checked upon me and told me that I had some viral infection and gave me a medicine course of 5 dayse. I became perfectly ok within 1 day of taking the medicine . the pain is all complteley gone now . but I have a question in my mind. I dint eat anything cold or fried that wld induce a viral infection I was perfectly all right then how come I got this sudden pain out of no where. Also, I keep having these painful muscle cramps on hands sometimes that lasts for seconds. ( I m very low on vit D n B12). I read on the net that these seizures happen cuz of brain tumour. Do I have a tumor?? MRI needed?