I haven't had any personal experience with this drug (or others of its type), but I looked it up on WebMD, and found this in the drug information provided by First DataBank:
"SIDE EFFECTS: You may experience dizziness, lightheadedness, drowsiness, tiredness, nausea, diarrhea, unusual dreams, leg pain, or vision problems as your body adjusts to the medication. If any of these effects persist or worsen, notify your doctor or pharmacist promptly."
You can find the full drug description for Atenolol here - although I'd bet you already have this since this type of information seems to be attached to all prescription drugs these days (or at least it is for my prescriptions).
Did you just start taking Atenolol? Or have you been using it for a while? It's got to be frustrating to get such opposite answers from two different docs. I hesitate to suggest introducing a possible third opinion, but have you asked your pharmacist? I've found pharmacists to be a pretty good source of information for things like this.
--- Denise