Recently, after fitness, the muscles are not sore, and the weight is alternately done, and there is no strength. Why?

Everyone is the same. Usually do not exercise, muscle relaxation, fatigue. At the beginning of exercise, muscles contract. Fat consumption leads to swelling and pain. It doesn't matter. Once you persist, you must persist. If you stop, you will still feel pain when you exercise next time. Life lies in exercise. You must insist.