Generally, the feeling of pain will not appear until the second or third day after exercise. If not, it means that the effect of exercise is not good and needs to be improved.

Generally, there is no oxygen before there is oxygen. There are many reasons, so I won't list them one by one.

The following is what I think is a good plan to lose fat and gain muscle:

http://www . jirou . org/jihua/jianfei/20 1306 14/7023 . html

If you have any questions, ask them.