Leg pain but can't walk

[tigers38]

My 3 year old grandson has leg pain but can't even stand on his left leg it hurts below his knee and its all day for 2 days now could it be a nerve problem.
It's not like i've heard of others that hurt at night he sleeps fine.

[margypops]

Has he been exerting himself more ,any running, is he at day care could they do exercises there, he may have pulled a calf muscle ,if it continues take him to see the Doctor and get it checked out..