What To Do For Leg Pain?

good afternoon sir,
i had problem with legs,two days back me and my neighbor carried 60 kg rice packet from ground floor to first floor between steps with hands but my position is tiet with bending legs in downway
problem:i standing only with straight legs but after above knees pain is somuch then when i started just bending so automatically pain is come with falling down to the ground (this started day after)
could you please provide solution immdiatly....