Sesamoiditis: This condition is characterized by inflammation of the sesamoid bones or the tendons surrounding them, located beneath the first metatarsal bone (big toe). The pain is typically exacerbated by activities that put pressure on the ball of the foot, such as walking or moving the toes, which matches the symptoms described.

Morton's Neuroma: Although typically described as pain between the toes, a neuroma affecting the nerve supply to the big toe could cause pain in the area described, especially if it involves the medial (inner) aspect of the foot.
Bursitis: Inflammation of the bursae around the joints or tendons near the base of the big toe could cause localized pain, especially with movement or pressure.
Tendinitis: Inflammation of the tendons connecting to the big toe, such as the flexor hallucis longus or brevis, could cause pain with toe movement.

Gout: Although less common in the first metatarsophalangeal joint (big toe) without a history of similar episodes, gout can cause severe, acute pain and should be considered, especially if there's a history of similar episodes or risk factors.
Infection (Osteomyelitis or Septic Arthritis): Infections in the bone or joint can cause severe pain and are medical emergencies. A negative X-ray does not rule out these conditions, especially in early stages.
Deep Vein Thrombosis (DVT): While less common in the foot, DVT can cause pain and swelling, and given the potential severity of pulmonary embolism, it should be considered, especially in patients with risk factors.

Freiberg's Disease: A rare condition involving avascular necrosis of the metatarsal head, which could potentially cause pain in the area described, especially in adolescents.
Kohler's Disease: Another rare condition involving avascular necrosis, this time of the navicular bone, which could cause midfoot pain but might be referred or felt in the area of the big toe in some cases.