question: Hi, Im a 35 yr old female and I started working out 2-3 times a week 9 mths ago. When under intense cardio, I experience one-sided (either right or left) chest pain right over my breast area. Im not sure if thats the subclavian artery.The pain is so intense that, while the cardio class is going, I put pressure with my hands on the pain, to alleviate it.Why is this happening? Should I worry?