**Core Concept**
The patient's presentation of sudden onset chest pain and palpitations, with a history of similar episodes in the past, suggests a condition that involves abnormal cardiac electrical activity. This condition is mediated by an abnormal electrical pathway in the heart that can cause premature contractions and potentially life-threatening arrhythmias.

**Why the Correct Answer is Right**
The patient's symptoms are consistent with **Tachyarrhythmia**, specifically **Paroxysmal Supraventricular Tachycardia (PSVT)**. PSVT is a type of abnormal heart rhythm that originates above the ventricles and can cause sudden onset palpitations, chest pain, and shortness of breath. The condition is often triggered by stress, exercise, or caffeine and can be self-limiting, lasting for a few minutes to several hours. The mechanism involves an abnormal electrical pathway, known as the **Wolff-Parkinson-White (WPW) syndrome**, which can cause the heart to beat too quickly.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not relevant to the patient's presentation of sudden onset chest pain and palpitations.
**Option B:** While coronary artery disease can cause chest pain, the patient's normal investigations and history of similar episodes make this diagnosis less likely.
**Option C:** Hypertension can cause chest pain, but the patient's symptoms are more suggestive of a cardiac arrhythmia than a blood pressure-related issue.

**Clinical Pearl / High-Yield Fact**
The patient's symptoms are consistent with a condition that can be triggered by stress or caffeine, highlighting the importance of taking a thorough medical history and performing a physical examination to identify potential triggers for the patient's condition.

**Correct Answer: C. Tachyarrhythmia**