Is it possible to have full control over brain?

I been taking it would be nice to turn on and off pain at will and slow down your heart beat, also to send oxygen to muscles your exercising to get stronger faster. maybe even remake your body slowly by reinforcing it with proteins and other minerals so you could live forever if you keep doing it or even remake your muscles and bones to higher the limit to the human bodie. If a person had full control over their brain would that be possible? Also is it even possible to have full control?