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1.The history with symptoms suggest possible cause could be muscle - skeletal pain, next possible cause will be
back pain radiating to the thoracic region followed by lung and cardiac pathologies.
2.In this case if she is my patient i would have examine first and followed be a x-ray chest PA view, ECG as initial investigations.
3.X-ray will give a over view of the chest and thorax possible causes and ECG will give a over view of cardiac pathologies.
4.I would recommend her to do some basic workup for muscle relaxation and apply
muscle relaxant if any localised pain.
5.Mostly there will not be any issue at this age probably positional muscle - skeletal pain, but can not take any risk with cardia and chest. so suggest get evaluated and treated accordingly. Good luck.
Hope i have answered your query,
any thing to ask do not hesitate to ask.
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