Is it worth of it , electricity and work on maintenance?
I dont know if its worth it for you. The servers Im currently looking at cost ~100EUR per year to run a full node. You usually get nothing in return in terms of money.
So if i dedicate my pc for node, can l use it for watching movies ,internet, mails?
Yes, bitcoin core sometimes hinders streaming, but you can just turn it off and back on later.
How you ern your fee?
You dont. Thats what miners do.