Hello dear, Other than chest pain due to involvement of Respiratory & Cardiovascular system, causes of chest pain include: 1. Strained chest muscles due to overuse 2. Chest muscle injury 3. Short-term, sudden anxiety with rapid breathing 4. Peptic ulcer disease 5. Pain from the digestive tract, such as esophageal reflux In your post, you have mentioned about taking a crash diet. So, the pain in chest may be due to production of gas in your stomach, which is irritating your diaphragm. Though symptomatic relief can be obtained by taking antacids, it will be better to consult a Doctor & get a physical examination done to rule out other causes. So that proper management steps could be taken. Wishing you a Good Health. Take care.