Hi..the infection seems to be viral in nature. The bone aches/ low back pain
is usually follows after a viral infection what's called as viral arthralgia
(Joint aches) and myalgia
. (Muscle aches).
Since you have joint replacement
its better to get rid of the infection to avoid spreading of the infection to the joint. Better to get checked for joint replacement area for any presence of infection at present by a orthopaedician.