The dr said I have a cyst on my pituary gland so what am I going to experience with this and what is a pituary gland

I cannot tell you what the cyst is or what to expect, you need to get that info from your doctor. He is the only one who knows exactly what your specific case is.

As for the pituitary gland: It is an endocrnie gland thata is suspended beneath the brain. It supplies many hormones that control many processes in your body.

So it all depends on where in the pituitary you have this, there are 2 portions to the gland itself, an anterior and a posterior.