Toenail pain in the foot may be caused by the following: 1. It may be nail fungus, which is usually an inflammation of the nail groove on both sides of the toenail, caused by accidental kicking or nail clipping, resulting in epidermal damage and bacterial invasion of the nail groove and bacterial infection over time. The nail is usually red, swollen, painful and even purulent if serious. 2, it may be caused by nerve inflammation of the toe, which causes pain in the toenail. 3, it is related to trauma, if the toenail or toe is accidentally kicked or hit by heavy objects, it may also cause pain in the local toenail.