1. Family and Relationships: The novel delves deeply into family dynamics, particularly the Morel family. It explores the complexity of parent-child relationships, particularly the bond between Paul and his mother, Gertrude. Gertrude's intense and sometimes stifling love for Paul creates tension within the family. Paul's relationships with his brothers and his father also play a significant role in the story, showing the impact of family dynamics on individual choices and development.

2. Love and Desire: Love and desire are central themes in ‘Sons and Lovers.’ Paul's deep emotional connection to his mother and his romantic relationships with Miriam and Clara are focal points. The novel examines the complexities of human desire, from the Oedipal love Paul feels for his mother to the passionate, often conflicted love he experiences in his romantic entanglements.

3. Sexuality: The novel addresses the characters' sexual desires and struggles. Paul's sexual awakening and exploration of physical intimacy with Miriam and Clara are central to the story. This theme highlights the tension between physical desire and emotional connection, as well as the societal expectations and taboos surrounding sexuality in the early 20th century.

4. Industrialization and Class Conflict: The story is set in a coal-mining town during a period of industrialization. It vividly depicts the harsh working conditions in the mines and the stark class disparities between the working-class characters and those in positions of authority. The theme underscores the struggles and social injustices faced by the working class.

5. Individuality and Self-Discovery: The characters in the novel seek to discover their individual identities and break free from familial and societal expectations. Paul, in particular, grapples with the desire to assert his independence and find his true self. This theme emphasizes the conflict between conforming to societal norms and embracing one's unique identity.

6. Nature and Industrialization: Lawrence frequently contrasts the natural world with the industrialized environment. Nature serves as a symbol of purity, solace, and inspiration for the characters. It is a stark contrast to the oppressive and unhealthy conditions of the coal-mining town. The theme illustrates the characters' connection to nature as a source of escape and renewal.

7. Psychological Conflict: The novel explores the psychological conflicts faced by the characters, most notably Paul's struggle with the Oedipus complex. His attachment to his mother and the emotional turmoil this creates form a central aspect of the story. This theme highlights the psychological complexities that shape the characters' relationships and personal development.

8. Freedom and Constraint: The characters navigate the tension between individual freedom and societal constraints. They grapple with the expectations of family, class, and gender roles, seeking a balance between personal desires and social obligations. The theme underscores the challenges of breaking free from societal norms and expectations.

9. Art and Creativity: Paul's artistic aspirations and creative pursuits are recurring themes. His passion for art represents a form of escape and self-expression. His journey as an artist reflects his desire for a life beyond the constraints of his working-class background and his family.

10. Emotional Alienation: The characters often experience emotional alienation from one another due to a lack of effective communication and understanding. This theme highlights the difficulty of connecting with and truly understanding one another, leading to feelings of isolation and miscommunication.

11. Conflict and Resolution: The novel is marked by various conflicts, both internal and external. These conflicts arise in personal relationships, family dynamics, and the characters' individual struggles. The theme explores how these conflicts are resolved or, in some cases, left unresolved, shaping the characters' lives and decisions.

These themes collectively create a rich and layered narrative that delves into the intricate relationships and inner lives of the characters, as well as the societal and environmental factors that influence their experiences. ‘Sons and Lovers’ is a complex exploration of the human condition and the forces that shape individual destinies.