I was exercising today and my chest started hurting around my sternum. This wasnt the first time Ive felt this pain but I cant seem to find a reason for when it hurts and when it doesnt. During the exercise, I was pulling my shoulders back and widening my chest.
Thanks for your question on Chat Doctor. I can understand your concern. By your history and description, possibility of musculoskeletal pain is more. So better to avoid heavyweight lifting and strenuous exercise. Avoid movements causing pain. Avoid bad postures in sleep. Take painkiller and muscle relaxant Chat Doctor.  Apply warm water pad on affected areas. You will mostly improve in 1-2 weeks with all these. If not improving then get done chest x-ray and ECG to rule out lung and heart related diseases. Hope I have solved your query. Wish you good health. Thanks.