Am I required to stand while saying the blessings over the Torah in the morning? If not, if I did stand for several years can I now stop?

You do not have to stand while reciting the blessings over the Torah, however many people are Noheg to stand as a Chumrah. If you stood until now, you do not have to continue on doing so since it was done by mistake. Rabbi Binyamin Bamberger