Hi,
Noted the history about your son having fever,
sore throat and now developed calve and
back pain.
The fever and sore throat persisting for such a long time produces toxins that can affects muscles, joints, heart and so on.
Other causes of pain in back and calves in particular also to be borne in mind are as follows:
Local
muscle strain.
Vascular problems in calves like DVT.
Hence I would advise him the following:
Consult your Doctor again for clinical evaluation.
Tests of blood and urine,
blood culture and sensitivity in particular.
Throat swab.
Change over to another antibiotic.
Add on anti-inflammatory.
Povidone iodine gargles.
Local examination of back and calves and further investigations if indicated.
Take care. Hope I have answered your question. Let me know if I can assist you further.
Regards,
Dr. T. Chandrakant, ENT & General Surgeon