What Causes Pain In Lower Back And Chills Along Despite Having Normal Blood Reports?

Question: I live in San Francisco Bay area.
Wednesday July 8, 7 PM I arrived at my daughters house in New York after two days of errands in XXXXXXX DC. I got out of the rental car and lost control... My body was shaking uncontrollably, my jaw chattering, I was unable to talk and was feeling FREEZING cold. It was 88 degrees with high humidity. We went into the house, but I was unable to keep up my end of a conversation due to the shaking from cold and the chattering of my jaw. I excused my self and took a hot shower. It did not help. I rolled up in blankets and bathrobes. I finally cuddled up to their large dog who kept my lower body somewhat warm through the night. Getting up to go to the bathroom was difficult because I was freezing cold and didnt want to move from the warmth.
While this is going on, I was SUFFERING from a weird pain in the lower right back of my skull. It started at the same time as the extreme cold.
It felt like I had an electric needle pushed into my skull, and someone was pushing a button sending electric shocks into my brain every 3-5 seconds. It was INTENSE. Going by experiences, my description of the pain was like a combination of needle-like pain of Gout, pain intensity of kidney stones and repetitiveness of final stages of labor pains all rolled into one spot in my skull.
So between the pain and the freezing cold I was feeling it was difficult to rest comfortably.
I stayed in bed with the dog keeping me warm until Thursday night when I came down to have dinner with the family. My first meal of any kind. I immediately went back to bed afterward. Still with incredible pain and freezing cold. During the night I broke into a sweat. Finally. In the morning I felt my body temperature was finally normal. So Friday around 11AM I went to the closest Urgent Care facility.
I complained about the intense pain I was feeling every 3-5 seconds and needed it to stop.
They said they understand that the pain was my issue, but they were more concerned about my fever.
I was surprised. I thought my fever had broke, but they said I was nearly 102 degrees. She also said I had low Oxygen Retention. The doctor called the emergency room at Stonybrook Hospital (Long Island) and "put me on the board". She told me to go immediately there.
They took blood, did a chest x-ray, gave me fluids by IV, EKG, MRI of my head, and took spinal fluid.
Everything came up negative. They could not find a reason for the fever.
They gave me medication for the pain through the IV, my pain went down and they let me go home at about 1AM (Saturday).
During the night, the medication wore off, and the freezing cold and pain came back with a vengeance.
I took a hot shower, grabbed the dog and took 600 mg of ibuprofen, and stuck a Salonpas pad into my hair, against my skull to maybe help stop the pain. I eventually slept for a while.
Saturday was the day I was to fly home to San Francisco. I kept myself medicated with the ibuprofen to deal with the pain.
This continued with a fever over 100 and pain in the same specific spot through Tuesday, doing a lot of sleeping (and crying).
Wednesday I went to my regular doctor who sent me to have another blood test.
I no longer have the skull pain. My temperature varies from normal to 100.
But i am extremely fatigued. I get up from bed, for just a couple hours and have to crawl back into bed.
I am not eating much, have an occasional headache, small stomach cramps
I have no answers, no advise, and do not know what to do.
I am tired of being tired. It has been 11 days since this started.
Can you help me?