Solve a tracking mystery

Anna800

When I updated myfitnesspal app it asked me if I wanted the app to track my steps and I remember saying no. I have a polar chest strap that I use the Polar app for calorie tracking. This started only when I started wearing the polar chest strap to workout. When I do strength training, after my workout, workout calories automatically get logged in my myfitness diary, yet they don't match the number in my polar tracker. Yet when I go for a walk, this doesn't happen. How is this happening? I don't have an apple watch.