Brief Answer: Hi Detailed Answer: Hi Thanks for posting your query on XXXXXXX Needle for blood test can cause complications like local redness, bruising (hematoma), inflammation of the blood vessel etc. This may itself cause pain in shoulder and arm and will get better when the local swelling subsides. Local infection of the blood vessel may need antibiotics. These are the usual causes of pain in the arm following blood test. Your concern is nerve injury. Mostly the nerve injury is to the small nerves that supply small area of skin and will not cause pain in the whole of arm and shoulder. It will also cause other symptoms like numbness of the distal parts and maybe weakness of the muscles. If you suspect that nerve has been damaged, then you need to consult your physician. If he thinks, then the nerve reconstruction may be tried. Vit B12 supplements can also be tried. Thus you need to consult your treating physician. Hope this helps. Dr Vaishalee

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