Is wanting to go to heaven Sin, According to sanatan Dharma?

The Gita says not to bother about going to heaven or hell! It says us to go on doing our own task without expecting any result from it! It is the almighty god who is the responsible for all of our doings! we can not avoid our workings as it is the god who is compelling us to do that!!God is the absolute soul and all of the creatures of this earth are the parts of it!! we should keep it in our mind and act in such a way lest it(our soul) may not be polluted!!