What Causes Sudden Swelling And Numbness In The Hand?

hi doctor...4years back i was travelling with my friend in bike, i was resting my left hand wrist on the seat...after reaching the place say 1hour travell my left hand became nam...from that time my hand strated swolling and pains badly which cudnt bere at all...i have taken many treatments which is not sloved........plzzzzzzz give me some solution doctor