The previous answers are exacto-mundo... however, chicken pox is caused by varicella-zoster virus which is the same causal agent for shingles later in life...
My son had chickenpox 3 times when he was younger - the first time he was covered from head to foot in spots and the next two times just on his face and chest.
yes you can get chicken pox twice and even later in life get shingles a few times. And guess what, my hubby as a child managed to get measles eight times. How about that for being greedy !