fever that comes and goes for 2 weeks is usually starts with viral infection , possibly upper respiratory tract infection since he had sore throught, after recovering from that he may got a superimposed ( on top of it )bacterial infection like strep which caused the fever to come again , a strep test is helpful . another cause of recurring fever with sore throught is reteropharyngeal abscess or peritonsillar abscess , which some times follow the supportive tonsillitis or throught infection , in that case the child s seems sleepy , toxic , unable to eat or drink and sometimes droll a lot luckily, with a proper physical exam, and images that can be excluded and roled out . I hope this helps