Thanks for writing to HCM
There may be various reasons for pain around left breast.
You need proper examination and investigations.
Investigations include routine hemogram,RBS,LFT,RFT,Lipid profile
of abdomen,Upper GI endoscopy
,ECG in all leads,Chest X -ray (PA).Further investigations may be needed after evaluation.
Causes of pain may be acidity,musculoskeletal,respiratory,cardiac etc.
Treatment can be given after clinical examination and investigation reports.
Examination of breast should also be done.
Get well soon.