Child having sore throat, sinus, headaches, pain in shoulders, ankle pain. Strep, thyroid, lupus negative. Suggestions?

11y/o daughter. C/o sore throat and sinus issues approx 4wks ago. Not severe enough to stay home from school. Seemed ok but sinus still problem. C/o sore throat again 2wks ago. Last thurs c/o tailbone pain - next day so bad she could hardly walk. That night she had fever (didn t take temp but she had night sweats off and on for 12 or so hours), pain had radiated to left shoulder - even sore to the touch. Very very tired. Sinus still issue. Been having h-aches for several weeks. Pain now in rt shoulder. Admitted she had ankle pain to touch for at least 2 mos that never goes away. Also, when she is finished voiding she ll go to stand up and more urine will drip out. At least tablespoon. Took to pediatrician who tested for mono (prior exposure), thyroid and lupus . Came back nega. Strep somewhat high but said not enough to raise eyebrows. Went back next day for strep swab - negative. Said she.ll refer to infectious disease dr if no better by Monday but so worried cause she s very athletic (v-ball, 9 yrs ballet, and track) she looks so tired and said why do I feel so unstable?