There's a stereotype in North American culture of the solitary, brooding artiste - hunched over a typewriter, a bottle of open liquor at the ready, a wisp of silvery cigar smoke curling about his head. There's no doubt that writing requires solitary time to think and commit words to the page. However, contrary to the brooding artiste stereotype, writing doesn't have to be completely solitary. You might even say that being an involved participant in the world is necessary to achieve great writing.
When you walk in nature and observe the goings-on around you, when you sit and talk with friends or observe people at a cafe, when you read about current events or learn about a subject that intrigues you, you are gathering material for writing.
Writing can be what you want to make it. You can be as solitary or social as you need to be. *You* determine your own identity - no one else can write your story but you.