Carpal Tunnel Syndrome: This condition is a common cause of hand pain, especially at the beginning of the hand, due to compression of the median nerve. It often presents with numbness, tingling, and pain in the thumb, index, and middle fingers, which can radiate to the wrist and forearm.

De Quervain's Tenosynovitis: Inflammation of the tendons on the thumb side of the wrist can cause pain at the beginning of the hand, especially with activities involving the thumb.
Ganglion Cyst: A lump or cyst that forms near the wrist joint can cause pain and discomfort, especially if it presses on a nerve.
Osteoarthritis: Wear and tear of the joints in the hand and wrist can lead to pain and stiffness, particularly in the base of the thumb and the wrist.
Repetitive Strain Injury (RSI): Overuse or repetitive movements of the hand and wrist can lead to pain and inflammation in the tendons and muscles.

Infection (e.g., Cellulitis or Abscess): Although less common, an infection in the hand or wrist can cause severe pain and requires prompt medical attention to prevent serious complications.
Compartment Syndrome: Increased pressure within the compartments of the hand or forearm can lead to severe pain, numbness, and tingling, and is a medical emergency.
Raynaud's Phenomenon: A condition that affects blood flow to the fingers and toes, causing pain, numbness, and discoloration, especially in response to cold or stress.

Tumor (e.g., Giant Cell Tumor): A rare tumor that can occur in the bones or soft tissues of the hand and wrist, causing pain and swelling.
Sarcoidosis: A systemic disease that can cause inflammation and pain in the hands and wrists, among other symptoms.
Gout: A form of arthritis that can cause sudden, severe pain and swelling in the joints of the hand, especially the base of the thumb.