Fevers, Chills, Sweats, and Back Pain Only at Night

Patient: I am a 38 year old man who otherwise before was healthy. Two weeks ago I had night fevers and chills (I was on a trip to Colorado at the time and it was extremely cold) complete with back sweats, and back pain. After the trip I was better, but a week later the symptoms have come back. The only thing is I feel well in the morning-afternoon but feel sick after 6:00pm. However, if I wear enough layers it doesn’t happen. These symptoms only come up in cold weather.