I saw an earthworm and i tried to lift him/her using a pen in order to take him/her outside. But suddenly it falls down over the grass and soil.
I wanna ask is he/she ok? Weather he/she got any injury or no?



Yes, the earthworm would have been fine. For small creatures with a low mass, dropping from almost any height is unlikely to do much damage, as impact with the ground (Force) equals mass x acceleration (F=ma). As gravitational acceleration on the earth is a constant 9.81 metres per second per second, you can see that for a large mass (a person or a horse, for instance) dropped from anything more than about 2m is going to generate a large force, which will usually involve at least broken limbs. 20m and a human or horse is going to splat, where as an earthworm would happily crawl away...