Yes I can put it as collateral however in that time can I still access my account as I have some things I would also like to get done. Also if I put my account as collateral will the person holding it be able to read my private messages and alter my stuff in any way?
Yes, of course, the person holding the account will be able to read through your private information and change things
1; however, you won't, because your account would have no value as collateral if you could access, and potentially recover it, unilaterally.
1 - likely password and email, in order to secure the account.