Thank you for the information,
There can be a few factors for chill feeling.
It can be due to an infection.
Different infections can cause such symptoms.
This can be bacterial or viral infection of the GI tract or gastroenteritis, flu, mono, meningitis, strep throat, pneumonia etc.
A collection of pus can cause it.
Another common cause is urinary infection but you do not have any such symptom.
Environmental cause can be a factor.
As it is going on for a few weeks, I would suggest to consult doctor and have a few tests to know the exact cause.
I hope this information helps.
I will be happy to assist, if you need any clarification.
Please feel free for any follow up query.