illegaloperation: attempted to create a lock file on a read-only directory: /data/db, terminating
From the question description it appears you are running mongod from your own account (user: makan).
Your invocation of mongod without specifying a configuration file or --dbpath would require this user to have read/write permissions for the default dbpath directory (/data/db). Since /data/db is only writable by user mongodb, a permission error is expected when mongod tries to write a file running with the permissions of makan: