Question 1: Does a Shield block an absorb action? I assume "no" since the rule says: shield protects a virus from being removed once....nothing about protection from being absorbed.
Why I ask the question: because it seems like a pretty weak shield if it can't block the absorb action.
Question 2: If I have more than one virus in an organ and absorb there, do I absorb my own virus(es)? I assume yes, since the rules say: "Place all the other Viruses in that Organ under your Virus"
Why I ask the question: it seems like your viruses are intelligent so may be able to decide 'to absorb or not to absorb.'
Someone else will be by shortly to give you detailed answers.