I know that the question you mentioned basically has nothing to do with your sleeping position. To put it bluntly, it is because of excessive exercise and slight strain, which has a lot to do with your long-term inactivity. I also had pain in the position you mentioned, and most of this pain was concentrated at the joint between the outer side of the arm and the upper and lower arms. Nothing serious. It happens to people who have just been trained. You will be all right after a few days' rest. You can practice your legs during the break. Abdomen. In fact, it is ok to continue to practice the upper body. It hurts when you start training. Just do a few groups. It still hurts when you get home. If you don't believe me, it will take a few days. Don't worry.