Is it true that in your past life you have died?

You live only once, there are no "past lives".

Another reply: Some religions believe in reincarnation. For those who believe in that, past lives (and future lives) are possible. Other religions believe otherwise - for example, that after death, your soul goes to a different world than this one, and doesn't come back, i.e., doesn't reincarnate. Which one is correct - well, that is hard to prove, one way or the other. I suggest you look at the teachings of different religions, and decide for yourself which set of beliefs is more logical, self-consistent, etc.