Polymyalgia Rheumatica (PMR): Given the patient's symptoms of bilateral shoulder pain, subjective fevers, elevated inflammatory markers (ESR and CRP), and the absence of trauma or infection, PMR is a strong consideration. The recent history of ovarian cyst and kidney stone could be coincidental, but the acute onset of systemic symptoms and musculoskeletal pain points towards an inflammatory condition like PMR.

Fibromyalgia: Although less likely given the acute onset and presence of systemic symptoms like fever, fibromyalgia could be considered, especially if the patient reports widespread pain and other symptoms like fatigue and sleep disturbances.
Rheumatoid Arthritis (RA): The presence of bilateral shoulder pain and elevated inflammatory markers could suggest early RA, although the lack of morning stiffness, joint swelling, and specific joint involvement makes this less likely.
Sarcoidosis: This condition can present with musculoskeletal symptoms, fever, and elevated inflammatory markers. However, other systemic symptoms or findings suggestive of sarcoidosis (like lung involvement) are not mentioned.

Septic Arthritis or Osteomyelitis: Despite the lack of evidence of infection, it's crucial to consider and rule out septic arthritis or osteomyelitis, especially given the patient's recent medical history and the presence of fever and elevated WBC. These conditions are medical emergencies.
Endocarditis: The combination of fever, tachycardia, and elevated inflammatory markers could suggest endocarditis, particularly if there's a history of valvular heart disease or intravenous drug use (not mentioned).
Lymphoma: Although rare, lymphoma can present with systemic symptoms like fever, night sweats, and weight loss, along with musculoskeletal pain. The recent onset of symptoms and lack of other explanations make it essential to keep this in the differential.

Relapsing Polychondritis: A rare autoimmune disorder that can cause musculoskeletal pain, fever, and elevated inflammatory markers. It often involves cartilaginous structures.
Adult-onset Still's Disease: Characterized by high fevers, salmon-colored rash, and arthralgias, this condition is rare and could be considered if other systemic symptoms are present.
Ehlers-Danlos Syndrome with associated hypermobile joint issues: While not directly related to the acute presentation, if there's a history of joint hypermobility or other systemic features, this could be a rare consideration for chronic musculoskeletal pain.