If I put a couple of lead bricks on my foot, there would be a definite sensation of a heavy, perhaps even painful, force. Calculating the pressure for 20kg of lead over a 100cm2 area of my foot, I get about 20kPa.

Now I stand underwater in a pool. If my foot is 2 m below the surface, then the hydrostatic pressure would be density x the depth x gravity, or 20kPa. Same as above. But in this case I wouldn't feel any pain or high pressure on my foot. Why the difference in sensation when under water, even though the pressure is the same in both cases?