62 yrs women suffers from mild fever (2 months), arthritis, frequent urination at night, pain through out the body & head; weight loss.what to do?

Infection: All these symptoms suggest usually infection more so chronic infections like tuberculosis, infective endocarditis are important ones to consider. Other chronic inflammatory conditions like polymyalgia may present in a similar way. Suggest to get checked by an internal medicine specialist.

See a doctor: Why not start by having that person see a doctor. She needs an examination and testing to be done.