Achilles tightness

After our class yesterday I had a lot of tightness in the Achilles area.
We were doing the weight on one leg bending with only half the cavities for the beginning of class. Wondering if this is related to the ankle flexibility that you have said I need to work on as it's inhibiting some movement. I only felt the tightness on the ankle that was in the rear, should I practice the same thing with the other foot in the rear?