Since your ECG is normal and BP was 100/70, the pain is less likely to be heart-related, especially if your doctor has examined you. Common causes include acidity/acid reflux, muscle strain, anxiety, or chest wall inflammation (costochondritis). If the pain increases with movement, pressing on the area, or deep breathing, it is often muscular. Try light meals, avoid spicy/oily food, and take antacids as advised. However, if the pain becomes severe, spreads to the arm/jaw, is associated with sweating, breathlessness, or persists continuously, seek medical attention immediately.