re-injury at ac joint possible?

About 5 years ago I injured my ac joint playing soccer. I never saw a doctor, but three PTs confirmed it was a grade III separation. I had the large bump and major pain. Someone taped the joint and and I let it rest. I've noticed that I never gained back the strength in my shoulder, but wasn't too concerned. The bump stayed but didn't seem so prominent after a while.
Three days ago, I began working out with Wii Fit. I did about three pushups with the twist to one side (so all my weight was supported on one side) and am now having problems at that joint. My range of motion and movement are ok, but the slighest touch causes a lot of pain. The area is exactly on the bump (which I am guessing is my clavicle. I can't hold the phone or a purse on that side. I imagine push-ups are a no no for me. Is there any thing I should be doing or should I just rest and wait for the [pain to resolve on its own? Should I consult a doctor?

Thanks for any advice.