Constant fever

Looking to see if anyone has gone through the same thing, 3 weeks ago my 8 month old had pneumonia after that she had a week of no fever then the week after that the fever came back but not as high now just 101 before it was 104 (when she had the pneumonia) she’s had this fever now for a week and I’m just concerned as to why she keeps getting these fevers doctors also don’t know and just think it’s a cold. I just feel so bad for her that she’s always uncomfortable and always wants me now.