Will having prostate surgery cause it to stop growing or will it continue to grow regardless?

Depends what surgery: If you had internal prostate surgery and don't take medicine to prevent prostate growth, it will slowly grow back. If the whole prostate was removed for cancer, then any regrowth is bad.

It = Prostate : The remaining prostate tissue does continue to grow after TURP (transurethral resection of the prostate), but generally not enough to ever require additional surgery.