21 years old i never smoked or drink. pain under my left breast hurts when i inhale lasted for a while felt pinches in my neck . isnt the first time it happened usually last for a couple of seconds but this time it was longer. no chest pain?

Anxiety/ Stress: Do you have a cough or fever? If not, it is most likely due to stress and anxiety. Continue to breathe deeply but hold your side to reduce the pain if you must. I would also suggest a neck massage to relieve some of the stress in the muscles of the neck. If you have shortness of breadth or cough get checked. You may want to evaluate what is causing the stress so you could ease off by meditation.