Hello and welcome to e health forum.
The description of your symptoms is very vague and does not help much to provide a probable diagnosis.
The possible causes for your symptoms could be due to conditions like asthma, musculoskeletal pain disorders, gastric reflux disorder, pneumonia, acute anxiety or stress - all of which can present as chest discomfort and difficulty or pain on breathing.
Hence you may need to consult a doctor, who can examine you and if needed order a few tests, including a Chest Xray if needed to know the exact cause.
I hope this helps.