Scaphoid Tenderness. In future?

I had a minor accident in bike on Sep 4th and was feeling pain in my left arm wrist. There was nothing visible in Xray. When Doctor pressed underneath area of thumb, it was paining. So Doctor diagnosed it as Scaphoid Tenderness and put a plaster cast from my left arm thumb till elbow. After 3 weeks, when we took X ray. Doctor said there was hair line crack and put a synthetic cast for another 3 weeks. On Oct 16th, he removed the cast. He didnt take X Ray, as I was not feeling pain in that thumb area. But I was feeling pain when I bend/swing my wrist. He said that pain will subsidy slowly and ask me to practise swinging my wrist. 2 weeks passed, still am facing slight pain when I bend my wrist (pain has reduced). I am not able to lift weight in that hand. My questions are: 1. How many more days it would take to cure completely so that I can drive bike? 2. When there is no sign of crack available at the initial stage how did it occur after 3 weeks? 3. Am I prone to fractures in future?