What Causes Pain And Discomfort Behind Ankle Over Stretching?

hi im not quite sure what i did. but it hurts behind my ankle like the ligiment behind my ankle on the back side. theres no visible lumb but i cant touch it and its been like this for 2 weeks and every pair of shoes i wear makes it feel like a horrible painful blister that you cant see under my sikin. and when i stretch it it feels like im slowly pulling something like a rubber band