Wrist Tendinitis or Tenosynovitis: This condition is likely due to the patient's recent increase in repetitive hand use from their workout routine and job as a server and flight attendant. The pain's location on the radial side of the wrist, extending to the thumb and index finger, and worsening with weight-bearing activities and twisting motions, are consistent with tendinitis or tenosynovitis, particularly affecting the tendons on the radial side of the wrist.

De Quervain's Tenosynovitis: Given the pain's location on the radial side of the wrist and its extension to the thumb and index finger, De Quervain's tenosynovitis is a plausible diagnosis. This condition affects the tendons on the thumb side of the wrist and is common in individuals with repetitive hand and wrist use.
Wrist Strain or Sprain: Although the patient does not recall a specific inciting incident, a strain or sprain could have occurred during their workout or daily activities, leading to the gradual onset of pain.
Carpal Tunnel Syndrome: The symptoms of decreased grip strength and pain extending into the forearm along the radial aspect could suggest carpal tunnel syndrome, especially if the median nerve is compressed.

Scaphoid Fracture: Although the patient does not recall a specific incident, a scaphoid fracture could have occurred and might not have been immediately noticeable. This diagnosis is crucial to consider because a missed scaphoid fracture can lead to serious complications like avascular necrosis.
Ganglion Cyst: While less likely, a ganglion cyst could cause pain and discomfort, especially if it compresses nearby nerves or tendons. It's essential to consider this diagnosis to rule out any potential cystic structures that might require intervention.
Osteonecrosis or Avascular Necrosis of the Wrist Bones: This condition, although rare, could be a consequence of trauma or repetitive stress, leading to the death of bone tissue due to a lack of blood supply.

Kienböck's Disease (Avascular Necrosis of the Lunate): A rare condition characterized by the death of bone tissue in the lunate bone due to a lack of blood supply. It could present with wrist pain, especially on the radial side, but is less common.
Gout or Pseudogout: Although primarily affecting the joints of the lower extremities, gout or pseudogout could theoretically affect the wrist, causing pain and swelling. However, this would be an unusual presentation.
Infectious or Inflammatory Arthritis: Conditions like septic arthritis or rheumatoid arthritis could cause wrist pain but would typically be accompanied by other systemic symptoms or signs of infection/inflammation.