Thanks for using Healthcaremagic,
Your available details suggest possibility of Urinary tract infection
and that is what you are taking treatment for.
Presence of kidney
stone increases chances of infection and the size was 4 mm hence it can be passed out spontaneously also.
Please continue to take treatment regularly and take plenty of fluids to keep urinary system
With available details there is nothing to suggest Osteomyelitis
but if they have something we do not know hence can not comment on that.
Hope this information helps.
Dr.Akhilesh Dubey M.D.