There's a great deal of pain in my left foot and ankle. Entire leg swollen

Hello. Thank you for posting.

If you don't remember injuring your foot, this pain and swelling can be caused by many things. For example, leg swelling generally occurs because of an abnormal accumulation of fluid in the tissues of the lower extremity. Many forms of arthritis and related conditions that affect the joints, muscles and/or bones can cause problems like pain, stiffness and swelling in the joints of the feet. If your pain is (as you say) 10+ you need to be evaluated by a doctor.

Helena