In regards, to your tight Achilles; a good way to lengthen them out on a continuous basis is to stand over the end of a step, rise through both feet to about 7/8 of your demi-pointe height, transfer your weight onto one foot and then very slowly lower the heel down and over the step, this helps to realign all of the fibers in the Achilles and can, over time, make it a little longer. Avoid strong, aggressive stretches of the Achilles as damage to this tendon will result in it getting tighter. You should be doing these rises, building up to three sets of fifteen three times a day, to help rehabilitate any Old Achilles tendon injury.