What Could Be Cause Of Chills With No Temp. I

What could be cause of chills with no temp. I have had recent UTI which I am going to check if it never was completely cured as recently Dr had me on two episodes of antibiotics but last visit said in house UA came out clear. but are there diseases or health problems that cause 2-4 episodes of chills during day that don't last long. My Dr doesn't seen to know why I am getting these.