Question

why do muscles pain when we do more hardwork than usual​

Answer 1

Answer:

When muscles are required to work harder than they're used to or in a different way, it's believed to cause microscopic damage to the muscle fibres, resulting in muscle soreness or stiffness

Explanation:

The resulting stress placed on the muscles, joints and bones causes fatigue and soreness that ultimately affects performance.

Answer 2

Hope this given image helps you