A simple cyst can be very uncomfortablr, but is not dangerous and will not turn into anything else.
If it is really painful, the fluid could be aspirated again, which should provide immediate, but probably temporary relief.
Cutting out all caffeine-containing products may also bring some relief.
I fully agree with "bluebutterfly2222" that simple cysts are harmless,they are not cancerous and will never turn into cancer
A simple cysts,is just a little sac filled with fluid. Since the cells in the fluid were tested and proven to be benign, then there is nothing to worry about.
The only time a simple cyst is removed,it's when it enlarges too much or causes you a great deal of pain.
If you are just uncomfortable with it being there,you could always seek a second opinion from a breast specialist/Surgeon who might decide to have the cysts aspirated or surgically remove the entire sac.
I really wouldn't worry if I were you,but if you are,you certainly have a choice to leave it as it is,or have it removed.