Isnt causing harm to yourself forbidden in Islam?Shia's?

i think its a bigger sin to blow urself up and use the name of Allah as a justification. and its is true that there are many shia scholars who disagree with using knives etc as a way of mourning for imam hussain. i cannot stress enough that only a minority of shias do this, however, the media will choose to show the ppl in iraq at the time of ashura (which amount to some hundred thousand), and everyone else umes that other MILLIONS of shias do the same. you couldnt be more wrong.