6 month old, repeating fever

I am a ftm, my son turns 6 months next week, right now he has a fever of 102. This started when he was going into 3 months. Ever since then, I’ve been having to take him to the hospital every month. He gets fevers once if not, twice a month. I’ve been to different hospitals, even the children’s hospital, they’ve taken blood/urine tests and nothing! It all comes back normal, but this is happening too constant for me to be comfortable. I’ve decided to just come on here and throw it out there to see if anyone has dealt with something similar, or if I’m just being too paranoid. I just want him better, hellllppp 😭