The bottom of the foot is a little painful, mainly due to the following diseases: 1, consider the plantar tendonitis, due to recent excessive sports, or long physical labor, weight-bearing activities, may cause more load on the plantar tendon membrane, over time the plantar tendon membrane will gradually produce strain and aseptic inflammation, manifested as plantar tendon pain, in the step down will appear local pain. 2, consider the heel subluxation bursitis The cause of heel bursitis is similar to plantar tendinitis, which is also caused by excessive weight-bearing activities, sometimes also related to wearing unsuitable shoes such as high heels. In the event of subungual bursitis, there is mostly pain below the heel bone. If the pain under the heel occurs after stepping on it, it is generally considered to be subacromial bursitis.