what forced tug on to return to Afghanistan

I suppose that you mean "What forces tug at Laila to return to Afghanistan?"

Laila realizes that she misses Kabul. She hears about life returning to normal. The coalition forces have chased the Taliban into hiding. She feels that her life in Pakistan is inconsequential. She is reminded of Hakim's words that Afghanistan will need her and her mother's words about seeing peace in Afghanistan to honour Ahmad and Noor. Laila tells Tariq that she wants to return to Kabul, and Tariq agrees.