Well, let's refocus the question slightly. I don't think it's so much a question of whether you like other forms of pain, but rather, if you like being tickled so hard that you're howling in agony (as you see at NEST when someone's tied down and has five or six sets of fingers at work all over), is that, by definition, a form of masochism?
And I think each individual lee will have his or her own answer. In my case, it's not so much masochism as liking the strange stimulation. (I'm a bad lee, though, because I'm only ticklish when taken completely by surprise, not when I ask someone to tickle me.)
But, ask me whether, when I'm the ler, the sensation I'm getting off on is sadism, and the answer is: absolutely. A few years ago at NEST I was tickling a woman's feet (that was the only part she made available), and she was just lying there placidly smiling the whole time; drove me crazy. (She was sweet, and if she's reading this, she should know, I still enjoyed meeting her and getting to tickle her--but I'm a tickle sadist, which means I want to hear some shrieks and moans.)