Cervical Spondylosis with Radiculopathy: The patient's symptoms of numbness and tingliness in the arms, along with pain and stiffness in the neck, are consistent with cervical spondylosis. The x-ray findings from January 2025 showing moderate disc space narrowing at C4-5 and C5-6 with early endplate osteophytic ridging support this diagnosis. The straightening of the cervical lordosis also suggests degenerative changes that could be compressing nerve roots, leading to the patient's symptoms.

Cervical Disc Herniation: Given the patient's recent history of physical therapy and the presence of degenerative disease, a herniated disc could be causing nerve root compression, leading to the symptoms of numbness, tingliness, and pain.
Thoracic Outlet Syndrome: This condition, which involves compression of the nerves and/or blood vessels that pass into the thoracic outlet (the space between your collarbone and first rib), could explain the numbness and tingliness in the arms, especially if the patient has been experiencing poor posture or has anatomical variations that predispose to this condition.
Medication Side Effects: Although less likely, the patient's medication, Amitriptyline HCl (Elavil), could potentially contribute to numbness or tingliness as a side effect, though this is not commonly the primary cause of such symptoms.

Spinal Cord Compression: This is a serious condition that requires immediate attention. Symptoms can include numbness, weakness, and tingling in the arms or legs, which the patient is experiencing. Although the x-ray does not show significant listhesis or spinal cord compression, clinical correlation is crucial.
Multiple Sclerosis: An autoimmune disease that affects the brain and spinal cord, leading to a wide range of neurological symptoms, including numbness and tingliness. It's essential to consider this diagnosis, especially if the patient's symptoms worsen or if other neurological deficits are found.
Vascular Causes (e.g., Subclavian Artery Stenosis or Thrombosis): Although less common, vascular issues could lead to arm symptoms due to decreased blood flow. These conditions are critical to identify due to their potential for severe consequences, including limb ischemia.

Tumors (e.g., Schwannoma, Meningioma): Rarely, tumors along the spinal cord or nerves can cause compression leading to numbness, tingliness, and pain. These would typically be identified on more advanced imaging like MRI.
Infectious or Inflammatory Causes (e.g., Discitis, Osteomyelitis, Rheumatoid Arthritis): These conditions can cause neck pain and neurological symptoms but are less common and would typically be associated with other systemic symptoms or risk factors.
Neurodegenerative Diseases (e.g., Amyotrophic Lateral Sclerosis): These are rare conditions that affect the nervous system and could present with a variety of symptoms, including numbness and tingliness, though they are much less likely given the patient's presentation and x-ray findings.