When the car is running and I open engine oil cap oil comes out like spray

For the most part it is normal. Have seen techs, me included in my younger days forget to install the oil cap and have the vehicle return with oil splatter all over the engine. The oil pump sprays oil to the camshaft to lubricate so if the cap is off, oil will spray out. Hope this information eases any worries you may have.

Yep, that can make a real mess under the hood. It isn't just the oil pressure that causes it though. The inside of the engine captures all of the fuel vapors and oil spray that is inside the engine as well as the tiny amounts of pressure that gets past the piston rings and this creates a small amount of pressure inside the engine. Normally this is controlled through the Positive Crankcase Ventilation System. It routes those gases back into the intake manifold so they can be burned in the engine. When you remove the oil cap you create a big hole for that pressure to exit, it takes the gasses and oil mist with it. On a modern engine running the engine without the oil cap on can actually cause the engine to run wrong. This is because the engine controls have to account for all of the air entering the engine, the large oil cap being off acts like a large vacuum leak.