The technical term for this pins and needles feeling is ‘Paresthesia’.
Most people are familiar with this sensation – it commonly occurs when a person has slept on their arm or left their legs crossed for too long. The feeling is caused by sustained pressure on a nerve.
Paresthesia is typically fleeting, but if it lasts a long time or occurs frequently a medical condition is likely to blame. Chronic paresthesia can be caused by a neurological disease or traumatic nerve damage. [source]
