I am a 24 yr old female. When i flex my foot and bend and straigten my leg back and forth, I feel a tendon or something pop back and forth on the right side of my shin. On the same leg I have also been getting a small lump on the lower front of my leg during my yoga practice. The lump doesnt hurt and only appears when balancing on one leg. The tendon or whatever it is that pops back and forth feels like a dull sting. Any idea what may be going on?