A misleading symptom
The pain worsened with movement, so a musculoskeletal explanation seemed reasonable. She used painkillers and delayed further evaluation.
The broader picture
She then developed fever, chills and nausea. The pain was higher in the flank than the lower back and urinary symptoms had preceded it.
The twist
The presentation was consistent with acute pyelonephritis rather than simple muscular pain.
Take-home message
Pain location must be interpreted with systemic and urinary symptoms. Fever plus flank pain and urinary complaints should raise concern for upper urinary infection.
Diagnostic principle: do not let the first plausible label stop the search when an important detail does not fit.
Educational note: This is a teaching composite, not a substitute for patient-specific diagnosis or treatment. Real patients require direct clinical assessment and appropriate investigations.