I sit up straight my arms bended as to type on laptop at my desk. After a short while my arms start to feel numb,painfull, short burst of heat sensation, index fingers going numb and sometimes tingling sensation. Also I could experience a sudden nerve pinch (which feels like a electric shock down my arm) when the elbow is in contact with the table and I bend my arm upwards.
Holding my arms above my head will increase the numbness and heating sensation in my arms. Only random movement of the arms subsude these feelings.
Not using my hands at all and holding them together in front of me on the desk in a relaxed position - also results eventualty in the same feeling.
The key here is that raising your arms aggravates the condition. This movement would normally relieve a pinched nerve in the spine.
So I'm thinking of a problem in the inter scalene triangle, a small space through which the nerves and artery to your arm pass. It causes a condition called Thoracic Outlet Syndrome, mostly a fixated first rib in the neck, also affecting the scalene muscles and the collar bone. Adson's test is the definitive examination, but it's difficult to perform unless one is experienced with the procedure.
Carpal tunnel syndrome is often associated with this first rib fixation, and there are some signs of CTS in what you describe.
Extending your wrists at the computer would also stretch out the Median nerve.
A cervical rib also needs to be excluded, it's not very common though.
What's needed is a careful, thorough examination, and perhaps some X-rays of your neck.
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