The causes of pain in the left toe are as follows: 1, toe tenosynovitis: mostly due to excessive toe flexion and extension activities can cause the toe tendons, flexor tendons, tendon sheaths to rub against each other, over time, will lead to toe tenosynovitis, manifesting as pain in the bottom of the foot when moving the toe, and in severe cases, accompanied by tendon sheath hyperplasia, resulting in a popping sound of the joint. 2, gouty arthritis: mostly due to high The gout crystals will accumulate in the first metatarsophalangeal joint of the toe, which usually causes acute pain in the toe when waking up, accompanied by redness and swelling. 3, bunion: the distal end of the toe bone is turned inward, which will repeatedly rub against the inner side of the shoe, and over time, bunions will form, thus causing pain in the toe.