It was not problematized the same way it was today (FYI, I wrote my dissertation on Victorian prostitution, and spent most of my PhD studying the history of sexuality).

Basically, the "problem" of masturbation began in the 1600s, when a Grub street quack published a tract called "On Onanism." Basically, it was a tabloid pamphlet that claimed a whole slew of physical and mental problems resulted from masturbation. http://books.google.com/books/about/Onania_or_the_heinous_Sin_of_Self_Pollut.html?id=O6Q_AAAAcAAJ

No one challenged this nonsense, and so 200 years later, the Victorians were positively in tizzy about all the horrible repercussions of prolific orgasm.

As to classical times, masturbation was just not a problem. It was something that silly satyrs did, for lack of a woman. (Link NSFW: http://www.mfa.org/collections/object/drinking-cup-kylix-depicting-two-satyrs-153478)

This may be a good source for learning more about masturbation in the Classical world: https://books.google.com/books?id=_6qLgVl4uikC&pg=PR7&lpg=PR7&dq=satyrs+masturbating&source=bl&ots=7hncYHyV0z&sig=lkSbPOOmrbH0BQZtdk-gwQ0R-uA&hl=en&sa=X&ei=6HKsVJ2qIYuryAT_9IKwBw&ved=0CCQQ6AEwAQ#v=onepage&q=satyrs%20masturbating&f=false

Additionally, Michele Foucault's History of Sexuality 2 and 3 are extensive studies of sexuality in the Hellenic world.