The pain can radiate down the arm with tennis elbow (lateral epicondylitis), that's fairly common. It's unfortunately one of those frustrating conditions that won't clear up over night. In terms of rest, dont put any weight on the arm if possible... are you still cycling? I would fo see your physio anyway, as they can work the forearm extensors for you and show you some of the stretches and wrist or elbow manipluations I mentioned - it really will help.
