Severe crippling leg pain that flares more during night

62F / 61kg/ 1.65 m , did a splenectomy 2 months ago due to splenomegaly (30cm),

-prescribed 3 pills Copred 20mg +vitamin D / calcium suppliments since 3 months which was tapered to 2 pills last friday

-prescribed Augmentin 3 times a day for 2 month after splenectomy which ended last friday

started experiencing severe leg / hand muscle pain since 3 weeks ago,pain is followed with thirst and dry mouth+ Urinary urge. pain intensify after sitting on toilet and is felt with every step while walking

paracetamol / Tramal reduce pain but dosn't eliminate it for long,

using ice reduce the pain until legs are moved again

starting last week (after copred taper+stopping augmentin) pain is now going up to thighs and lower back and followed by high temperature and chills .

Already talked to a doctor and going to do necessary tests on monday but the cause of pain is still unclear

NFS results show high WBC 58K whose cause is also unclear

test shows the presence of an infection and patient was put back on Augmentin + another antibiotic

any idea what to do what's the cause ?