I am a 50 year old male and recently started walking to lose weight. during my walk my right foot at the ball just behind the toes starts to hurt. no?

Start slowly: I'd start by making sure you have properly fitting, supportive and appropriate walking shoes. Next be sure you're easing into your walking gradually. If you're having pain already, take a short break from walking, rest/ice the area, and the ease back into it more slowly. If this isn't effective get checked out.

Neuroma: You may be developing a neuroma, growth on the nerve etween the toes. You may just have metatarsalgia, pain to the bones of the foot. Either way try ice, and a soft innersole. If persists, see a podiatrist.

Stress fracture: Sometimes when you start an exercise program such as walking or running, there's a chance of developing a stress fracture. This needs to be evaluated by a podiatrist with x-rays and careful examination.