Costoclavicular syndrome: This condition, also known as costoclavicular space syndrome, involves compression of the neurovascular bundle between the clavicle and the first rib, leading to pain and tenderness in the clavicular area. The absence of a reported injury makes this a plausible explanation due to possible repetitive strain or poor posture.

Clavicular osteitis: Inflammation of the clavicle can cause pain and tenderness, often without a history of trauma. This condition might be related to overuse or infection.
Subclavian vein thrombosis: Although less common, thrombosis of the subclavian vein can cause pain in the area of the clavicle, especially if it leads to swelling and inflammation of the surrounding tissues.
Cervical spine referred pain: Issues with the cervical spine, such as herniated discs or facet joint syndrome, can refer pain to the clavicular area due to the complex innervation of the neck and shoulder region.

Thoracic outlet syndrome (TOS): While TOS can present with neurological symptoms, some forms (like the venous or arterial types) can cause pain and tenderness around the clavicle due to compression of the subclavian vessels. Missing this diagnosis could lead to serious complications, including permanent nerve damage or vascular compromise.
Lymphoma or metastatic disease: Although rare, pain and tenderness over the clavicle could be the presenting symptom of lymphoma or metastatic disease involving the lymph nodes or bones in the region. Early detection is crucial for treatment and prognosis.
Osteomyelitis of the clavicle: Bone infection can cause localized pain and tenderness. Given the potential for serious complications, including sepsis or chronic infection, this diagnosis should not be overlooked.

Friedreich's disease: A rare genetic disorder that affects the nervous system and can cause musculoskeletal pain, including in the shoulder and clavicular area, though it's more associated with progressive neurological deterioration.
Relapsing polychondritis: An autoimmune disorder that can cause inflammation of cartilages, including those near the clavicle, leading to pain and tenderness. It's a rare condition but should be considered in the differential diagnosis due to its potential for significant morbidity if not treated.
Eagle syndrome: Caused by an elongated styloid process or calcified stylohyoid ligament, this syndrome can lead to referred pain in the shoulder and clavicular area due to compression of nearby nerves.