Why do my ears hurt when im swimming?

why do my ears hurt when im swimming? ik its because of the water pressure but even when i equalize the pressure they hurt because they get water in them! is it some allergic reaction to the chlorine or what??? its not the pressure, but they hurt just like when ive got swimmers ear but as soon as i come out of the water and empty the remaining water out, they stop untill i go under water again! ive managed to get a "air pocket" in my ears, but as soon as i get arms length underwater, the pocket bursts and water rushes in, causeing them to hurt. ive tried ear plugs but they dont stay in and are a menace. what should i do????