In Breaking Bad, Walt always refused to take help from his mother and tell her about his cancer. Why did he behave this way, was there some problem between them?
Walt was a very proud and stubborn man, and refused help from anyone. Gretchen and Elliott offered to pay for his cancer treatment, but his pride wouldn't allow him to accept their offer. Even when his own son set up a fund raising website, Walt couldn't accept the money, explaining to Skyler that "It's charity!". So it is likely then that he also wouldn't accept any help from his mother.
As far as not telling his mother about the cancer at all, I don't think that is ever really explained in the series - there seems to be no indication of any long running feud between Walt and his mother. All we know about Walt's childhood is that his father died when Walt was a young boy.
I think we can chalk it up to the fact that Walt was proud and didn't want anyone to know about his problems or to feel sorry for him.