You may have added in too much flour or your baking soda was too old. Knead gently to avoid chewy gluten from forming. Always knead until it just comes together.u003cbr/u003eu003cbr/u003eTaking too long with kneading the dough can also play a part. Baking soda starts reacting and releasing gas as soon as it comes into contact with buttermilk. We don't want the gas to escape before it's baked.