I had a simular experience had a kidney infection (1st one never had kidney/bladder infection before) given oral antibiotics once completed symptoms went away but ran a low grade (100°) fever that was constant and every night would get the chills with shaking and teeth chattering that lasted 20-30min. Also had a dull pain in right flank. They ran a ct scan looking for appendicitis and found i had a large staghorn (sturvite) kidney stone. Was ok as long as i was on antibiotics but once completed the fever would come back. Was in and out of hospital givin iv antibiotics for 3 mos. Test always negative for infection. Kidney ended up at 8% so they removed the whole kidney. 2 wks later got a call from the hospital to come in pathology found tuberculosis in the kidney!.not saying thats whats going on with you but just giving information that was not ordinary.
@Sammie12312.. any update when did the headache and neck pain subside?
Update: I forgot to mention I also have pain on both sodes of my neck along with the headache.