Hi Faisal,
You can start learning about these subjects on your own but I would encourage you to eventually continue your education at a university. These subjects are too complex to completely understand on your own. You need to be challenged by professors and students to verify that you really understand the material. If you are very capable and motivated you will begin to learn something but you need to be in an environment of learning to master these subjects. Additionally you will not be exposed to the latest trends and state of the art with these subjects.
Would you like to be treated by a person who learned medicine on their own.
Mike