Cervical Radiculopathy: This condition, often due to a herniated disc or cervical spondylosis, can cause pain that radiates down the arm, numbness in specific fingers (including the pinky, which is typically associated with the C8 nerve root), and is consistent with the symptoms described. The intermittent nature and specific distribution of numbness support this diagnosis.

Thoracic Outlet Syndrome (TOS): This condition involves compression of the nerves and/or blood vessels that pass into the thoracic outlet (the space between your collarbone and first rib). It can cause pain in the shoulder and arm, numbness, and tingling, especially in the pinky and ring fingers. The symptoms can be intermittent and exacerbated by certain positions or activities.
Myofascial Pain Syndrome: This condition involves pain and inflammation in the muscles and their surrounding soft tissues. It can cause localized pain and referred pain patterns, including pain along the shoulder blade and down the arm, depending on the specific muscles involved.
Peripheral Neuropathy: Although less common to present with such localized symptoms, peripheral neuropathy can cause numbness, tingling, and pain in the arms and hands. The involvement of the pinky finger could suggest ulnar nerve neuropathy, but this would typically not cause pain along the shoulder blade.

Acute Coronary Syndrome (ACS): Although the patient denies chest pain or shortness of breath, atypical presentations of ACS, especially in women, can include arm pain or discomfort without the typical chest pressure. It's crucial to consider cardiac causes, especially if there are risk factors for coronary artery disease.
Pulmonary Embolism (PE): Similar to ACS, PE can have atypical presentations, and while the symptoms provided do not strongly suggest PE, any condition that could lead to sudden death or severe morbidity if missed should be considered, especially if there are risk factors for thromboembolic disease.
Spinal Cord Compression: This is a medical emergency that can present with pain, numbness, and weakness in the arms or legs, depending on the level of compression. The absence of leg symptoms or bowel/bladder dysfunction does not rule out this condition entirely.

Pancoast Tumor: A type of lung cancer located at the apex of the lung, which can cause shoulder and arm pain due to invasion of the brachial plexus, as well as numbness in the arm. It's a rare condition but should be considered in smokers or those with a significant smoking history.
Arteriovenous Malformation (AVM) or Other Vascular Anomalies: These are rare conditions that can cause a variety of neurological symptoms, including pain and numbness, due to abnormal blood vessel formation. They are less likely to present with the specific pattern described but could be considered if other diagnoses are ruled out.

Can you describe the pain in more detail (sharp, dull, burning, etc.)?
How long have you been experiencing these symptoms?
Are there any specific activities or positions that exacerbate or relieve the pain?
Have you noticed any weakness in your arm or hand?
Do you have any history of trauma, neck or back injuries?
Do you smoke or have a history of smoking?
Have you recently traveled or been immobile for an extended period?
Do you have any family history of neurological or vascular diseases?

Inspection: Look for any visible deformities, atrophy, or swelling in the neck, shoulder, or arm.
Palpation: Check for tenderness along the spine, shoulder blade, and arm.
Range of Motion: Assess neck and shoulder mobility.
Neurological Exam: Perform a detailed neurological examination including strength, sensation (light touch, pinprick), and reflexes in the arms, focusing on the distribution of the symptoms.
Special Tests: Consider thoracic outlet syndrome tests (e.g., Adson's test, Wright's test) and assess for cervical radiculopathy with Spurling's test.