It sounds like you have what we call fever
of unknown origin. This is what we call a fever that occurs without an obvious cause. I would suggest that you schedule an appointment with infectious disease specialist
first for this issue. That problem has a very standard work up. The first step is to undergo a physical exam by either an internal medicine physician or one that specializes in infectious diseases. The purpose of this exam is to look for any signs of infection that might be responsible for the fever. This workout will usually also include a chest x-ray to look for pneumonia, blood cultures to look for infection in the blood, a urinalysis to look for urinary tract infection, and sometimes an echocardiogram to look for infection of the heart. You can also include a CT scan
of the chest abdomen and pelvis. The purpose of this is to look for infection and other causes of your fever such as an abscess. Additional work up will include blood test to look for rheumatological and inflammatory conditions that could also cause a fever. Finally, if nothing is found a short work up for malignancy such as lymphoma which can sometimes be the cause of fever should be done. Again, I would suggest that you schedule an appointment with infectious disease specialist first for this issue. They have performed FUO (fever of unknown origin) workups many times.