Hello dear I understand your concern Discomfort under breast could be due to heart problem, panic attack, gastritis, musculoskeletal pain. I would suggest to consult your primary care physician and undergo chest x-ray, ECG scan, CK,CK-MB, routine blood test to confirm cause. If above test will come normal then nothing to worry. Take anti inflammatory drug like diclofenac and muscle relaxant like tizanidine Proton pump inhibitor like pantoprazole Take proper rest Avoid spicy/fatty/oily food Do regular exercise like walking and yoga Avoid stress, take healthy diet, drink plenty of water and. Hope this may help you Best regards Dr. Sagar