It may be because of long-term inactivity, sudden intense exercise, incorrect posture or insufficient preparation for exercise, which leads to slight wear of meniscus next to knee and ligament strain. It is recommended to go home and rest first, and then go to the gym after the knee pain stops. I hope you will do enough preparatory exercise when exercising lower limb strength in the future, otherwise it will be counterproductive and cause physical injury. I hope the landlord will recover soon and hope to adopt it ~