what is the difference in 'shall' and 'should'?

Question

which is grammatically correct - shall i do it?
or should i do it?

also pls tell me the difference in usage of shall and should .. im very much confused...

Answer 1

I shall do it....confirms that you intend to do it in the future
I should do it..means that you are aware that it the best course of action, but doesn't neccesarily mean that you will