Cervical Radiculopathy: The patient's symptoms of numbness and tingliness in the arms, combined with neck pain and stiffness, suggest a cervical radiculopathy. This condition occurs when a nerve root in the cervical spine is compressed or irritated, leading to symptoms in the arms. The patient's age and the fact that the symptoms are persistent throughout the day support this diagnosis.

Cervical Spondylosis: This condition involves wear and tear on the discs and joints in the cervical spine, which can lead to compression of nerve roots and symptoms in the arms. The patient's age and symptoms of neck pain and stiffness make this a likely diagnosis.
Thoracic Outlet Syndrome: This condition involves compression of the nerves and blood vessels that pass through the thoracic outlet, which can lead to symptoms in the arms. The patient's symptoms of numbness and tingliness, combined with neck pain, make this a possible diagnosis.
Medication Side Effect: The patient is taking Amitriptyline, which can cause numbness and tingliness as a side effect. However, the presence of neck pain and stiffness suggests that there may be an underlying condition that is contributing to the symptoms.

Spinal Cord Compression: This is a serious condition that requires prompt medical attention. Symptoms can include numbness and tingliness in the arms, as well as weakness, bowel or bladder dysfunction, and gait disturbances. Although less likely, it is crucial to rule out this condition due to its potential for serious consequences.
Multiple Sclerosis: This is an autoimmune disease that can cause a wide range of symptoms, including numbness and tingliness in the arms. Although less likely, it is essential to consider this diagnosis due to its potential for significant morbidity.
Stroke or Transient Ischemic Attack: Although the patient's symptoms have been present for two days, it is still essential to consider the possibility of a stroke or transient ischemic attack, especially if there are any other symptoms such as weakness, facial drooping, or speech difficulties.

Vitamin Deficiency: Deficiencies in vitamins such as B12 or vitamin D can cause numbness and tingliness in the arms. However, these deficiencies are relatively rare and would typically be associated with other symptoms such as fatigue, weakness, or gastrointestinal disturbances.
Peripheral Neuropathy: This is a condition that causes damage to the peripheral nerves, leading to symptoms such as numbness and tingliness in the arms. However, this condition is relatively rare in a 41-year-old male without a history of diabetes, trauma, or other underlying conditions.