Chills at night

I completed chemo on the last day of 2018, finished radiotherapy in March and had a bilateral mastectomy with DIEP reconstruction 3.5 weeks ago.  I’m will be on hormone treatments for 10 years (I was diagnosed at 40).

Just about every night in the last week, I have been waking up shivering, as if my foobs are freezing.  I also get hot flushes, but it this is mostly manageable.  

Would the chills be the body’s reaction to the surgery I’ve had?  I don’t have a temperature.

thanks