What diagnosis is suggested by a patient presenting with neck pain, palpitations, and a tender thyroid gland?

The presentation of neck pain, palpitations, and a tender thyroid gland points towards subacute granulomatous thyroiditis, often referred to as de Quervain's thyroiditis. This condition typically follows a viral infection and is characterized by inflammation of the thyroid gland, which can lead to pain and tenderness. The inflammation can affect thyroid hormone release, causing symptoms like palpitations due to hyperthyroidism.

Patients often describe a painful and swollen thyroid, which aligns well with the physical examination findings of tenderness in the thyroid region. These symptoms contrast with other thyroid conditions that may not present with significant pain or discomfort localized to the thyroid gland. For instance, Graves' disease generally presents with a non-tender goiter, and factitious thyrotoxicosis would usually not involve tenderness of the thyroid but rather a history of ingestion of thyroid hormones. A thyroid abscess, while it can cause neck pain and tenderness, typically presents with signs of infection such as redness, swelling, and systemic signs like fever, which are not mentioned in the vignette.

Thus, subacute granulomatous thyroiditis is suggested by the combination of neck pain, palpitations due to hyperthyroid symptoms, and the tenderness of the thyroid gland.