Brief Answer:
Most likely musculoskeletal pain

Detailed Answer:
Hi! Welcome to Healthcaremagic. Thanks for sharing your concerns with us. We will try to help you in best way possible. First of all it's sad to know what you had been going through lately.

Based on the history you have shared, it seems most likely to be musculoskeletal and can originate either from muscles or acromioclavicular joint however cardiac element should be ruled out even though chances are very low as it isn't how usually cardiac pains present still every left sided chest area pain should have an EKG at least.

A chest X-ray to rule out lung pathology as well X-ray of shoulder joint may be needed. OTC analgesics like acetaminophen or Ibuprofen can help with the pain.

Muscle relaxants like orphenidine or tizindine may also be needed. Physiotherapy and precautions to lift heavy weight with the affected arm should be followed.

Rarely stomach pain can refer to this area so should also be ruled out based on associated symptoms if they lead towards chronic acidity or regurge. If so antacids like omperazole may also be needed.

Hope this has answered your query. If you have any questions please feel free to ask. Regards

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Brief Answer:
Based on such one such symptom it is too early to say that

Detailed Answer:
Hi! Most common possibilities are those that we have discussed and it's too early to predict myeloma based on one such symptom. Skeletal survey or XRay of revealed lytic bone lesion rest of work up may be needed for myeloma but it's a very rare possibility. Regards

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