Person who reads a lot never feel lonely even if he is alone. A prisoner in a cell reads a lot.
You might need to learn how to communicate others, but I don't think you have to always hang out with your friends.
I think, everyone, who is alone, feels lonely. Some people suffer from this while others enjoy.
That's the difference between introverts and extroverts. An extrovert person tends to be out-going and feel comfortable being with others. An introvert can also enjoy other people's' company but to a lesser extent, and needs more time for him/herself alone. Our genes play a role in determining our degree of intro/extroversion.