You must pay attention to relaxation after fitness. Your muscles are hard, one is lack of exercise, and the other is not stretching after exercise. Stretching means stretching the exercised muscles as much as possible. Pay attention to pulling slowly, even if it hurts, try to pull to the limit. Stop playing, it will hurt.

Keep practicing! People who exercise regularly will also be sore. Don't be afraid. If the movements and amount are appropriate, everyone should have muscle aches after each exercise (including professional fitness athletes such as Schwarzenegger). Just get used to it. But the muscles are hard.