Hospital said shortness of breath was from anxiety, yet i'm not anxious, i'm calm as can be. my breathing keeps bothering me. it's persistent for 3wks?

Keep Following Up: A hospital visit is like a snapshot - things change and so keep following up with your doctor to track any changes in your condition. I presume an evaluation for serious heart or lung problems did not reveal an answer and, at your age, anxiety would be more common than other serious problems. Ask about asthma, a heart defect or valve problem and an unusual condition like sarcoidosis.

Deep breathing: Shortness of breath can be due to anxiety. While you continue to explore possible causes and perhaps see other professionals for evaluation, you can always try some breathing activities, which are beneficial to anyone (with or without anxiety). Try an internet search for abdominal or deep breathing as well as progressive muscle relaxation and start practicing.