A pain snail is a person who carries around too much emotional baggage and tends to be quite slow. Painsnails are always moaning about how miserable they are but never do anything to change things. A Painsnail often has low self esteem and low morals - Painsnails can not keep their pants on but almost always regret their encounters. They are incapable of holding down relationships and when in a relationship they mess it up for themselves by cheating.
There appears to be a "painsnail" in almost every TV drama.