The causes of foot discomfort are as follows: First, you can consider plantar muscle strain, such as frequent weight-bearing, sports activities, up and down stairs, hiking, or heavy physical labor, such as walking with a burden, backpack walking, too much time will appear plantar muscle strain, so you will feel sore and swollen discomfort on the bottom of the foot. Second, consider plantar tendonitis, plantar tendonitis is also caused by frequent weight-bearing walking. The plantar tendon membrane is subjected to excessive load, and aseptic inflammation of the tendon membrane can occur, which can also manifest as pain and discomfort on the bottom of the foot. Third, consider the ankle canal syndrome, when the cervical nerve is compressed at the ankle canal, it can manifest as plantar numbness and painful discomfort.