i was wondering if some one can tell me if there are 3 warriors fighing the same monster and 1 of the fighter will use shild bash to push the monster 10ft away will the other 2 fighers get opertunity attack when the monster leaves there attack rage ?

no, forced movement does not cause opportunity attacks. 

Attacks of Opportunity can only be taken against a creature that moves voluntarily.

You can avoid provoking an opportunity attack by taking the Disengage action. You also don't provoke an opportunity attack when you teleport or when someone or something moves you without using your movement, action, or reaction. For example, you don't provoke an opportunity attack if an explosion hurls you out of a foe's reach or if gravity causes you to fall past an enemy.

So a shove does not provoke an opportunity attack because it doesn’t use the creatures movement. 

But a spell like Command (flee) causes the creature to use its movement and does provoke an opportunity attack.