I am sorry to hear about your pain. You should meet with your primary care physician
for further evaluation, but here are some possible explanations for your symptoms. If you recall any trauma or injury
to your left arm, neck, back, or chest, you may have a muscle or bony cause for your pain. Repetitive stress or heavy lifting could also cause this sort of pain. Medications like Advil or Motrin would generally work well for muscle/bony pain, and symptoms would hopefully improve after approximately 2 weeks. Sometimes problems in the lung can cause back pain, especially when taking a deep breath. Although usually uncommon in young adults, shortness of breath and back pain with deep breaths could indicate a blood clot. If you have fevers and a productive cough, infections such as pneumonia
could be the explanation for your pain. Finally, infections or problems in the abdomen can sometimes cause pain in other locations (called referred pain). This would usually cause pain over the shoulder rather than the space below the shoulder blade, although it is still a possibility. Your physician will be able to perform a more careful assessment, and evaluation should include a thorough review of your symptoms in addition to a back, shoulder, lung, and heart exam.