I do not understand why my left arm is hurting really bad and I cannot move it.

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2 Answers

These messages are for mutual support and information sharing only. Always consult your doctor before trying anything you read here.
Less serious causes of left arm pain involve physical injury or overuse. Common injuries include a mastectomy, left brachial plexus injury, left arm, wrist, or hand fracture, sports-related strains or sprains, rotator cuff injury, and tendinitis. You can rest the arm or wear a sling or brace to better help support it.
Do you mean that the arm is so painful that you just can not move it because moving it will aggravate the pain?

If you mean arm paralysis, then it is bad, especially when it occurs suddenly, because it means that you may have a stroke.

If you mean you just cannot move it because of the pain, then there are just too many possible explanations for the arm pain. Better see a bone doctor and get examined.
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