You are right to be concerned because foot pain is not normal. There are a number of common foot problems that can cause pain in the ball of your foot. Stress fractures, nerve inflammation (neuroma), joint inflammation (capsulitis), tendinitis, or a sprain can all be possible causes.
I recommend that you seek care from your podiatrist for an evaluation, that may include x-rays, to find out what is causing your foot pain. Once a proper diagnosis is made, an effective treatment plan can be implemented so that you can Zumba again in no time.