Yes my dear it is normal :) Unless it becomes painful, in which case you might have a yeast infection, which is quite common. But under normal circumstance the vagina is similar to an aroused penis, blood flows to the area which is how you have heightened sensory within the area. So, yes this is normal and yes this will obviously happen before climax.
I think it is ask a doctor asap!How to wash your vagina?
What do you mean by the shower head thing?
And its normal if your vagina turns red