Hi,
Thanks for posting your query.
With the available described symptoms, there appears to be possibility of acute
viral fever.
Presence of rash, fever with
body ache suggest the diagnosis.
As such there appears to be no correlation between present symptoms and
lead poisoning.
You should consult with your treating doctor/ internal medicine specialist and should go for thorough check up.
You should go for
ultrasound imaging of lump at the back of neck.
Meanwhile you should take proper bed rest along with analgesics and muscle relaxants.
Take care,
Dr. Mayank Bhargava