The novel Sons and Lovers is one of the best examples of a genre that really came into its own in the early twentieth century—the autobiographical novel (other autobiographical novels of that period include Somerset Maugham's Of Human Bondage and Joyce's Portrait of an Artist as a Young Man).

Most of the characters, locations, and, to a certain extent, events are based on real life. Like Paul Morel's mother, D.H. Lawrence's mother was born into the middle classes, but married into the working classes. Similarly, Morel's Father was essentially the same character as D.H. Lawrence—a working class Nottingham miner. From these and other similarities, the reader can presume that D. H. Lawrence based Morel on himself.

For example, like D. H. Lawrence, Morel has a closer relationship with his mother than his father, favoring intellectual pursuits over physical labor, and like Lawrence, Morel has an intimate relationship with a close friend of the family who in the story is called Miriam Leivers. The real life person who inspired Miriam is a woman named Jessie Chambers.

As D.H. Lawrence expert Harry T. Moore states,

The tormenting relationship of Lawrence and Jessie, which was to last for about a dozen years, became one of the principle theme of Sons and Lovers (1913), with Lawrence as Paul Morel and Jessie as Miriam Leivers.

In the aftermath of D.H. Lawrence's death, Jessie wrote a book about her relationship with D.H. Lawrence called D. H Lawrence: A Personal Record.

Yes, the story of Paul Morel is based on D. H. Lawrence's own life. The eNotes essay "Lawrence's Novel as a Bildungsroman" (linked below) discusses how the author uses the fictional Morel to explore the difficulties of negotiating the "the pull of family and culture to cultivate his individuality." See also the other eNotes articles below.