I injured (sprained) my left wrist, elbow and shoulder 4 weeks ago by falling off my pushbike. How long do you think ignorant could take for me to be?

That depends... I assume you wonder how long the sprains last - which is typically 6-12 weeks, but could be more or less depending if you reinjure yourself due to overuse. After you heal, you will want to gradually build up your muscles with gentle range of motion stretches and exercises.