I Have Pain In My Elbow?

pain is only when i fully extend my elbow it feels really weird like it hurts on the inside its a sharp pain when i extend it fully i feel it only when i play sports and the ball hits my hand when its fully extended it hurt it first while playing football i was going for a pass n i extended my arm to catch it n when i did that ball pushed down on it whil extended n its been hurting ever since i hurt it again yesterday in basketball sum 1 tried to pass it to guy i was defending they threw it hard i deflected it n it hurt all day in my elbow